How long can cats be left by themsleves?

I left mine alone over the weekend . They had 2 big bowls of cat chow and the ever lasting water pump machine with endless water . I would say 3 max .

I have left my cats home alone for up to a week. I have a self feeder that holds about 7 pounds of food and I have a dish pan that I fill with water for them. They are far more comfortable in a place that they are used to than to go to a boarder. I have a Siamese that would be beside herself if I took her to a cat boarder. I am positive that the stress would kill her. She was a rescue from the humane society and she loves her home so much that if I just try to take her to the vet she vomits and has diarrhea in the crate. So I refuse to put her through that stress. If you leave plenty of food and water for your cats they should be fine. Just expect to HAVE to spend a lot of time loving them when you get home. But if you are concerned about leaving them home alone then you give them plenty of attention anyhow. Just make sure that someone knows that the cats are there. I have a sticker pasted on one of my windows in case of an emergency stating that I have cats and dogs in the house if they are to be rescued. Oh, make sure that your closet doors are closed and that they have a big litter box that you cleaned just before you left on the trip. It saves unpleasant surprises in strange places.

I've left my cat for 3 days. I just made sure she had a mountain of dry food. As for water, I left a huge bowl of water out too. As a secondary precuation, just leave the toilet lid open(and clean it if necessary). The cats can use that as an emergency water supply if needed. They will be ok for 3 days.