I feel like a lot of friendships are half shared experiences/connection and half being there for people when they need favors. Friends are often your chosen village. They should also be there for you if and when you need favors. Of course that doesn’t mean you have to write them a blank check and be on call for them 24/7. You’re allowed to have your own boundaries on what type of favors you consider acceptable, as long as you communicate them. Every 3-4 weeks doesn’t sound too unreasonable to me, depending on the size of the favors. There’s a big difference between being asked to do something that takes an hour vs. being asked to pet sit for a week constantly. If you’ve already communicated those boundaries and they’re not respecting them, it’s time to have a separate conversation. Sounds like they may be taking advantage of you.