You can choose to feed a mature sourdough everyday, every 3 days, or every week, give or take a couple days. Sourdough is hardy and resilient once it has matured (been well kept for a couple weeks after the initial activatation). If you want to feed it every 3-10 days, just feed the starter atleast triple its volume, and stick it in the fridge (and repeat weekly, to keep it active). You will still see it feed (and double), just at a much slower pace. Use your best judgement for when it looks like its deflating and needing a new feeding. Adjust its food amount if it ate more quickly than you wanted it to.
Sometimes we all need a break, including your starter! You don't need to stress too much about leaving it unattended if you can't find a babysitter! Many people have stories of pulling out a long-forgotten starter from the back of their fridge and still being able to revive it. When you return, you will just want to take it out to room temperature for a few days and give it some regular feedings to rebalance and revive it. Don't try to feed it large amounts of food before leaving- just feed it normally (otherwise it may struggle competing with spoilage bacteria).
Extended Breaks / Back-up Storage
If you can't feed it and won't be able to for a month or more, stick the starter (in its container) in the freezer. OR, you can dry a bit, by spreading the starter thinly on a clean cookie sheet and covering it with papertowels until completely dry. Store it in a dry, cold dark place (you can put the dried flakes in an envelope in the fridge or the cupboard) and re-activate it later! It should keep for many months with both of these methods (even a year or more possibly). They will need about a week or so of re-activation when brought back out of storage.