I leave my pair of keets alone for two days and no longer than three days. Every few weeks I take a two hour drive to visit my parents and I usually spend two nights there. I have a home security camera looking directly at their cage and it live streams to my phone. I check in on them multiple times a day. I make sure every one is present (my two keets and two bourkes) and looking healthy. Usually when I check on them they're happily bouncing around being crazy. If anything seemed to be wrong I'd immediately start my trip back to take care of whatever problem. I know this can't prevent every accident and depending on the scenario I might not get back in time to help but the same goes for having someone physically going to check on them. If they're only going to check one to two times per day they could easily walk in on an accident and be too late do do anything. Overall, leaving your birds no matter what precautions you put in place is risky.
I leave each pair of my birds with two full food bowls, two water bowls, and they always have access to a water bottle but I haven't seen them use it yet. I put their water bowls in the higher spots to help keep them clean, and usually all four bowls are in good condition when I get back. They don't get poop on their bowls very often. I also have extra bowls I can put in if I'm expecting to be gone three days instead of the usual two. I'd rather overload them instead of them not have enough.
Before I leave I check their toys and remove any that could be a risk. I give them new toys if needed to help keep them busy while I'm gone. I usually give them some millet to forage for. I leave the curtains open so they get some light during the day and they go to sleep when it gets dark.
I'm hoping to move closer to home soon so I won't have to leave them anymore but for now having the camera on them gives me some peace of mind, I really hate leaving them.
This is what I can see from the camera on my phone. It's not the best but I can see all 4 birds and check in any time I want.