The problem with Kats

The Kat continues to vomit at least once of a week so I've come to the conclusion that a change of food is in order. I did a little research, finding that Science Diet makes lots of different pet foods so one of them must be right for my cat. Tonight I stopped by Petco on my way home to run in and pick up cat food. After perusing the bags of food for a while not finding any hairball control formula I realized dogs do not get hairballs and moved over to the cat aisle. Science Diet makes a plethora of cat foods. There's Adult Hairball, Adult original, Adult Chicken and Rice, Light Adult, Hairball Control Adult, Sensitive Stomach Adult among others. And those are just the dry foods. Then there's the senior foods for cats over 7; this year my cat celebrates her 8th birthday. The seniors get much less choice, Senior Hairball, Senior Original and Senior Advanced Protection (body armor not included). I wanted Adult Light Hairball Control which according to the website is available, however it was not to be found. Why is there no Senior Light Sensitive Stomach Hairball Control is beyond me. Maybe I just live too much in the Starbucks world. I settled for Indoor Cat Adult which combines weight control and hairball prevention. So I ask you makers of fine cat food just what are the senior indoor cats supposed to eat?