Don’t forget to feed your pet (like in real life) and make sure you take full use of it (not like in real life). You get 4 hours of extra power if you feed your pet. It is recommend to only feed your pet if you really can play for 4 hours, otherwise you are wasting the power of your pet.
However, there is a trick;
As you might already know every player gets a free pet for 24 hours. It’s useful, if you just play for a few minutes per day. It is free and won’t cost you any money, because you don’t need to feed it.
If its really worth it to buy a pet and food for it really depends on how you play the game. It can be really useful, but if you are just playing on an average level a free pet is enough.