Well, I'm on both sides. I am a massage therapist, and I eat in locally owned restaurants once a month or so.
Me tipping others- I tip 20 percent, unless the service is bad. I leave a much smaller amount, and a note stating why. Empty water is my biggest issue.
Around holidays, I do nudge it up at my usual spots. New place? Not so much.
Customers tipping me- I see a slight increase in tips from people not using gift cards. Gift card users split almost 50-50 on their tipping. My regulars tipped heavily this month, but most skipped the previous month.
I don't solicit or expect tips, I just see the numbers in my billing paperwork. The spa collects all credit card tips and they come in my check.
Cash tips are down, though.
I haven't tipped postal carriers in years. They rotate so much. I think if you have a connection with a carrier, it might be different.