When dealing with guinea pigs, many mistakes are made by a simple action: visiting a pet shop. People imply by default that every and any product offered by a shop for a certain type of pet is legit and safe. Unfortunately, it is not. One of those products is a leash for guinea pigs, which in fact is a very bad idea. Cavies have very delicate spines and bone structure which can not tolerate stress generated by hamster wheels. Avoid at all costs.
Similar product, and our mistake number two, is a Hamster Wheel, which some people promote that it also works on cavies. But here is a fact: it does not work on cavies. Moreover, guinea pigs could seriously hurt themselves on that thing because of their delicate spines and bone structure which can not tolerate such stress.
Getting at number three, by putting your pet on the direct sunlight on the hot summer day, by believing that he/she need to get some sunlight and to get out of the shades. But in fact, guinea pigs have LOW tolerance for high temperatures and could suffer a heat stroke. They do prefer shades, after all, they are prey animals.
Single Guinea Pig is a mistake number 4. It could be easier to maintain and control, it is cheaper, maybe less messy, but the fact is, guinea pigs are social (herd) animals and they need company besides their human caretakers, no matter how much time they spend with their pets every day.
Small Cage is one of the most common mistakes, and here it is on number 5. Small cages do not enable fair air circulation, and there is a serious danger of higher toxic gasses fluctuation inside the cage. Smaller cages are messier, need cleaning more often, more unhealthy for your pet, and not to mention that cavies need larger living space because, well, they tend to grow.
Mistake number 6 involves improper diet - one of the most dangerous mistakes. Giving your pet human junk food, dairy products, wrong vegetables, too much fruits, or anything that is not on the "safe list", creates a danger for your cavy. Seeds are also a mistake because they are mostly empty calories with no significant nutritional value, plus bonus feature: they are choking hazard. Learning guinea pig food preferences is one of the most important prerequisites for having a guinea pig for a pet.