If we use the 20% rational then housekeeping should really be paid much much more. A waiter with whom we interact with for a few minutes here a few there, and they clean up at 20 %, compared to housekeeping. A Bell boy 10 minutes up to your room gets say 5 bucks.
But housekeeping who while never seen knows us the most intimately spends the most time in our service and proportionately get paid the least. These people clean our toilets.
We generally do 15-20 % for wait staff depending on service.
Never (or very rarely ) use bell boys, but then likely 4-5$
Cleaning staff we leave money every day on the bed. When my husband travels alone on business he says he leaves $5 , but room is kept very , very tidy, towels folded etc.
As a family we always make up our beds, pick up our towels, generally leave the room tidy, but we are 5 so there is more of a mess I am sure. Then we would leave $10. Might have to rethink that again, for instance on our last stay we were at the DLH , at a rate of $190 plus taxes. Well that would put it in the $20 a night range if we went with the 20% range. Those ladies work so hard, and for a pittance I am sure.