First and most obvious is having someone there to feed your feline. More than that though is that some cats like play with their water bowl splashing the water everywhere. Having someone there to clean up the mess and refill the bowl every day not only makes sure you'll come home to a clean space and a well fed and hydrated kitty.
2. Preventing escape
Cat's can be social creatures. They like to be petted, tended to, and given treats. Your cat gets use to seeing you every day, so when all of a sudden you aren't around any more they may become lonely or agitated. they may decide to try and escape to go looking for you or they may feel abandoned and decide to go find another family to live with. Whatever the reason your cat may try and escape. Having a consistent cat sitter for them to get to know, talk to them and give them the attention they crave will help your cat maintain a sens of routine while you're gone and makes sure they are still there safe and sound, and if they do get out it wont belong before the cat sitters stops in, see they are gone and can take action to get them back home.
3. Playtime with the cat sitter
Some cats especially younger more energetic ones like play time. If you are gone for a long time they may get angry or nervous. Some cats get agitated when they are left alone too long. They may act out by knocking things over scratching furniture or pooping outside their cat box. Having a cat sitter to com by and play wit them for a bit will help them burn off that extra energy and help them relax and makes sure they don't get agitated so they don't get tempted to turn your sofa in to a scratching post.
4. Clean litter box
Cat's are pretty clean but maintaining a hygienic litter box is still important. Letting a litter box go too long with out cleaning may cause it to develop extremer odor, and some fungus or bacteria can take hold. This may cause the cat to decide to find somewhere else to poop. A cat sitter can make sure your cat's box stays nice and clean while your away.
5. Household security
Lots of things can happen while you are gone that don't directly have to do with your cat but can have an effect on your cat. Sometimes weather can swing wildly, especially here in Chicago land. Pests may try to penetrate an empty house or even burglars may try to break in; all of which can post a threat to your cat and your home. A cat sitters can adjust the thermostat if all of a sudden the temperature spikes or plunges; Pests will be scared off by the daily activity in the house and most burglars will be decided to pick an easier target.
There are many reasons why hiring a cat sitter is a good idea, but perhaps most of all is peace of mind. Knowing you have someone back home taking care of your precious kitty will make sure you can enjoy your vacation or focus on your business trip without need to worry; and that is pricless.