​​Experts on 15 common mistakes we make, from skipping painting prep to encouraging bad habits in a puppy

<span><em>All illustrations by Edith Pritchett</em></span><span>Illustration: Edith Pritchett/The Guardian</span>
All illustrations by Edith PritchettIllustration: Edith Pritchett/The Guardian

The dog trainer: playing too much with your puppy

The important thing many owners fail to do with their dog is encourage it to calm down. There is so much emphasis on playing and running. People think they have to play with their puppy because it wants to, but this encourages the dog to be constantly active. It then doesn’t settle well and its behaviour can quickly become problematic. Spending time teaching dogs to walk calmly on a lead and rest at home should be a priority. To learn how, go to a class or follow online advice.
Ben Marsh of Balanced Dog

The dentist: snacking too often

Each time you eat your mouth becomes acidic. If you snack five or six times a day your mouth is going to be constantly acidic, which means you are more prone to getting cavities. Try to eat only four times a day – three meals and a snack – to allow your mouth to return to a more alkaline state in between.
Dr Shahryar Namjoo

The IT support person: buying a cheap inkjet printer

So many people buy a £25 inkjet colour printer but end up spending £60 on ink every two months because they use small, expensive cartridges that run out or dry out quickly. It’s a consumer scam. Buy a black and white laser printer instead, and if you want colour photos printed send them to an online photo printer.
Jason Dagless

The cleaning influencer: wiping away antibacterial sprays too quickly

Lots of people use an antibacterial spray cleaner to disinfect surfaces – but not many leave it to work for a vital few minutes before wiping it down. If you read the instructions, it usually tells you to spray and then leave it: this is so the enzymes in the cleaner have time to effectively kill the bacteria. Give your surfaces a spritz then do another job while you are waiting.
Laura Mountford

The dry cleaner: ignoring label instructions

Be wary of people recommending cleaning shortcuts, and don’t Google quick fixes. We see people who have bought something that says “dry clean only” but they’ve had a go at hand- or machine-washing it, and it has shrunk, gone a weird shape or lost its colour or print. We’ll do our best to fix it: if it is a sizing issue, we can usually bring it back to about the right size, but colour loss is much more difficult to reverse. Get items to a professional. Conor Slevin

The plumber: fitting taps the wrong way round

With either a mixer or two-tap set up, hot must be on the left and cold on the right. This is so everybody – even people who are visually impaired – knows that if they turn the lever to the left or turn on the left tap, the water is going to be hot. It’s a rule that DIYers often get wrong. Before fitting or replacing a tap, run the water to make sure you know which pipe is hot and which is cold, and make sure you connect hot to the left tap connector.
Becky Bates

The dermatologist: letting wounds dry out

Wounds – whether they’re surgical wounds or injuries – heal faster in a moist environment. This can reduce the formation of scabs, which helps improve the cosmetic outcome of the scar. To keep things moist, wash the wound – don’t rub or scrub, just let soapy water run over it – then pat it dry, add a thin layer of Vaseline and put a dressing over the top. Change the plaster or bandage every day.
Dr Ellie Rashid

The head lice expert: quick-fix treatments

It’s a mistake to chuck a chemical treatment on hair once and think that will deal with the head lice. The secret is to break the head louse life cycle and remove eggs that haven’t hatched, which takes a bit of time. The most effective way to deal with them is to follow NHS advice: regular wet combing, which removes live lice and eggs. Comb every day or every other day until you find no trace of live lice or eggs.
Dani Knapp of Nitty Gritty

The fashion stylist: not thinking about your personal style

Clothes are designed to look enticing, so people often buy pieces they like the look of but which don’t suit their lifestyles, work with their existing wardrobe or fit their true tastes. Instead, I advocate the My 3 Words method: choose three words to define your style – French, bohemian and comfortable, say – then remind yourself of them when you’re shopping, steering away from anything that doesn’t fit at least one. Buy clothes you’re going to get lots of wear out of and that suit your everyday life, rather than a fancy cocktail dress “just in case”.
Alexandra Fullerton

The baker: not adding salt to sweet bakes

People are used to seasoning their savoury cooking: it is now seen as common sense to add salt to pasta water. But with baking, people fear salt because they don’t want biscuits or cakes to taste salty. I think people need to remember that salt is there to make ingredients taste more like themselves. And some of the best compliments I get are about salt crystals cutting through the sweetness.
Nicola Lamb

The florist: putting cut flowers in the kitchen

Fruit and vegetables produce ethylene, which can cause flowers to ripen and age. Some are particularly susceptible – anemones for example. Others naturally have a long vase life, such as tulips, ranunculus and larkspur. Another mistake is not giving vases a good scrub, because bacteria can shorten the flowers’ life.
Milli Proust

The personal trainer: seeing exercise as punishment

When it comes to exercise, people often think that if it hurts, if they are sweating or feel pain, that is good. But this is wrong because if you associate something with pain, you won’t continue. I try to get people doing things they enjoy, be it swimming, cycling or a sport they played when they were younger. It is about enjoying the process and building resilience, so when exercise does get tough, you are motivated to keep going.
Louis Quaye

The painter and decorator: skipping the sanding and filling stage

When it comes to decorating, 80% of the job is about preparation. I go to people’s houses where they have done the painting themselves and haven’t prepped anything. I mean dusting down, sanding, filling. You need to fill everything two or maybe three times to get the desired effect. And all the furniture needs to go into the middle of the room and be sheeted up so you can work around it.
Joe Lye of Brushes Decoration

The nanny: giving kids mixed messages

What I am seeing a lot at the moment is a child asking for something and the parent instinctively saying “no”, without giving an explanation. The child then starts crying and throws themself on the floor, so the parent then says, “Oh, OK, you can have it.” The child is confused because the parent is saying no but then saying yes. When your child asks a question, think whether the answer can be yes somehow. For example, you could say, “Yes, that’s a great idea. We’ll definitely do that, but we’ve just got to do this first.” It takes away the negativity. If you are usually a yes person, on occasions when you do have to say no, your child will be much more likely to accept it.
Louenna Hood

The physio: training too hard as a beginner runner

With all the hype around half marathons and other running events, many beginners go straight from never having run to following a strict training plan. Often their muscles, tendons and joints are not used to the load and they soon get injured. Then they tend to run through pain, worsening the injury further. To avoid this, start slowly: run no more than three times a week and don’t run on consecutive days. Wear a good pair of trainers and have your gait analysed at a running shop, because people often run in trainers that don’t suit their feet. Listen to your body: if you feel pain, get it checked out by a physio or give yourself more rest days.
Hollie Maskell