Gratuity being charged directly to your bill usually only happens with fairly large parties - it's not rampant or anything.

If i'm happy with the service, I usually tip between 15-20%.

If service is poor it can be as low as 5-10%.

Probably 15%

20% and up because my Dad put himself through college back in the day just on tips and I respect that. If the service is shit 10% or less. If I have little left after the bill I'll just leave the change. Oh and sometimes I scribble little notes with advice on it :P

I never tip based on arbitrary notions of what to give.

I base it entirely on need. In some situations, I give $2-3 USD if it's a minor meal. However, I've tipped up to 100% if I feel the waiter/waitress really needs it.

In Ohio, wages for a tipped employee are $3.15 USD, whereas minimum wage is closer to $7.00 USD. I try to make sure that's reached when I eat a meal somewhere.

Isn't minimum wage an arbitrary notion mandated bby congress.  maybe congress should mandate gratuity

It is, but since waiters recieve tips, they're exempt from that law. They're usually paid ~$3 an hour.

The UK doesn't have a tipping culture like the US. Even so, waitresses and other restuarant workers are paid less than minimum wage in some places.

I work in a restuarant kitchen for less than mimimum wage, but make it up in tips.

I usually tip between 10-15% which is more than most in the UK.

You could call it the minimum hourly wage, but that's generally the assumed meaning for wage in English (American for sure. I assume it's the same for British?). Sometimes it can mean such things as daily or weekly. What's the generally accepted meaning of wage there?

It depends on the service, but I'd say generally between 10-15%. Sometimes less if very poor.

The paychecks are very small, around $2.50 an hour, because their primary income comes from tips.