I agree with you, the longer the resident lives at a community the bigger the reward should be.
I had a 'Menu for Better Living' at some of my properties. It was designed like a restaurant menu. The resident could pick items from the menu worth up to $200 for the first year, $300 the 2nd year, $500 the 3rd etc.
Items might be carpet cleaning, Maid service, Handyman service, Free cable TV and/or internet Free Newspaper, designer blinds, new vinyl in the kitchen, new fixtures in kitchen & bath, new carpet, accent walls, their trash picked up a their door, no charge for heating, etc. There are so many things that can be included that cost very little and make the resident feel valuable!