i do this all the time. i've done it for up to 5 days... it doesn't mean there won't be any accidents, but there could be accidents while you were at work - you can't be there 24/7! if you'd worry, see if you can find someone reliable to stop by each day, just to check up.
I have gone off for 3 days without anyone checking up on the cats. I leave several water bowls, a faucet in the bathroom on slow drip, 4 litter pans and plenty of dry food. However, that being said, I just turned down an invitation to visit friends in NY because I won't leave baby boy Cosmo for that length of time - too much trouble for him to get in to!
I wouldn't leave mine for more than 24 hours without someone checking up on them. I would ask everyone you know (and would trust) if they can drop by a couple of times to make sure they're ok in the hope that someone is willing to do it.
the longest i have left mine is over night. if its the weekend i make sure i have someone come round at least once a day to top their food up make sure they havent spilt there water. and for a few cuddles. if i cant get anyone to do it , then i dont go.