Guided trip question

[cklenske]

Planning a short trip to RMNP in Colorado in a couple of weeks. Thinking about taking a half-day guided trip while we are there, and have been checking out the local guide services, and know the approximate costs, equipment, etc. Only thing I'm not sure about is the gratuity. What's customary for a half-day trip? Just don't want to look like a dimwit or a cheapskate when I'm there. Thanks.
CJ

[Normand]

15-20% sounds about right.

http://www.midcurrent.com/articles/trips/tipping.aspx

[LadyFisher]

Since I was one I'll make some really mad at me. If your guide actually helps you and you learn some by all means the 15 -20% tip is just fine.
If you catch the biggest fish of your life a little more is appropriate. If he's been drinking and swears like a sailor (no offense meant) NO TIP!
It's okay NOT to tip if everything goes wrong and the guide really doesn't do anything or help you.