I think 3/5 days is too long, as they will get stressed.
When ours were kittens we used catteries. There was one cattery we used which turned out to be terrible. Metal cages exposed at the front to the elements and the noise of a fast road. Our cat hated it. What was worse, the cat in the cell next to his was really noisy and mean sounding. When we went to pick our boy up, I could hear a strange noise, like a child howling loudly and continuously. It was him, our cat! I put him in his harness so he could walk passed the mean cat and finally see him, and he turned and hissed and spat at him! He was lovely to me and the children, and jumped up to DH for a cuddle. I swore I'd never leave him at a cattery again.
We tried cat sitters for a while, but at £6 a visit, and 2 or 3 visits a day needed to let them in and out, it was too expensive. We tried taking the cats with us on holiday too, with litter trays, but they would get out and one disappeared for 3 nights! (he turned up exhausted and slept continuously in a dark cupboard for the rest of the holiday).
Now we they eat dry food from an automatic hopper (3 feeds a day) and they have cat fountains which get cleaned every 2 or 3 days. In the summer, I prefer to half fill the hopper and fill it more often, to keep the food fresher for them. They have a cat flap to get from the utility to garden and another in the utility door to get to the rest of the house, that way we can limit them to one room for their safety if needed.
We have got here by degrees, as one cat would still like it if we left litter trays when we are away.
Last time we went away, friends looked in on them every day, topping up food and cleaning water fountains every couple of days. Next holiday they have agreed to do the same, but are away themselves for a few days, so will ask a neighbour to drop in then.