Here are my tipping policies. For some reason, I almost always get good service in restaurants. It may be because they have some way of sensing that I'm a good tipper or that I go to the same restaurants and they recognize me. I sense that some restaurants are especially nice to people they haven't seen before because they want the people to come back.
I take the total before tax, round up to the nearest $5 and take 20% of that (an easy calculation). At buffet restaurants, I typically tip 10%.
The minimum tip is $2 per person. Many restaurants are trying to keep lunch costs down and I can eat lunch for $6 at a restaurant (trick: get water to drink; soft drink prices are outrageous and iced tea is ever worse).
I don't drink so I don't know what the rule is for alcoholic beverages. When I'm paying for other's drinks, I believe I have kept the 20% rule but trimmed the amount a bit.
Sometimes I order carryout for another person along with my meal. If I do this, I tip on the carryout amount as well. The servers I have worked with go overboard to make sure that the carryout meal is correct and brought to the table at the right time.
If I use a gift card or receive a major discount, I disregard that when paying the tip (i.e. I tip on the full amount before the gift card or discount). This would also apply to a meal purchased with a Groupon deal.
I don't mind if my server has to share tips with the busboy but if a restaurant has tip pooling or a similar system and I hear about it, I will no longer patronize that restaurant. My tip is intended to be a payment to my specific server.
If I receive bad food or service, most of the time it isn't the server's fault. I sometimes reduce the tip but usually I will avoid patronizing that restaurant for a while. I rarely complain to the manager; I just move on.
I saw a post on Facebook recently about the sad life of a server and why she really needed tips. This is not my concern and I really don't want to know about my server's personal life. My tip is not done out of sympathy, it is a reward for good service. I tip the same whether my server is a millionaire or on food stamps.
If you can't afford the tip, don't patronize the restaurant. Go to a less expensive restaurant or to a fast-food place. Or, radical idea, go to a grocery store and fix your own meal. I remember paying a $30 tip at the Montgomery Inn Boathouse but the service, food and view were impeccable. I was happy to pay it.
Riverboat cruise with dinner
I usually tip 10% of the meal cost (buffet rule). If there is a live piano player, I usually tip him a dollar or two.
Hotels and motels
My room rate is typically less than $100 per night. I tip $3 per day including the last day to the cleaning folks. I have found that I need to put a note next to the tip; one day, I just left $3 on the table and it was still there that night.
I avoid valet parking like the plague. It's just a habit of the rich that I prefer to avoid. If I did use valet parking, I would tip $2. Many years ago, I would have tipped a dollar, but I like to adjust for inflation.
Ballpark or Football Stadium
If I get an usher who insists on wiping down my already clean seat, I tip a dollar. I put the dollar in my side pocket ahead of time so it's not so obvious that I'm tipping.
On a recent move that took two hours, I tipped $5 per person. I made sure each person got his $5; I didn't want the driver pocketing everyone's tip.
Mechanic or Tow Truck Driver
I don't tip these folks. I wonder if the tow truck driver is already ripping me off so I'm not going to tip him. Usually, the driver is just happy that I'm not yelling at him; you would not believe the abuse they get when they're just trying to help you.
I took a taxi a couple of years ago in Chicago with three other people for just a few blocks. There is a charge on the meter for extra people but the driver put in four instead of the correct three. He only cheated himself as I had already planned to pay him $10. I don't take cabs much so I'm not an expert here.
I have been going to the same barber for over 20 years. When I first started with him, he was less expensive than my previous barber, so I tipped him $2. I have tipped him $2 ever since and now he is even less expensive than Great Clips. He also owns the shop and supposedly you're not supposed to tip the owner, but I don't care.
In the South, I have used restrooms with attendants. Sorry, I don't tip to pee.
Anything I've missed?