there is no standard tipping % for guiding
Why all this recent talk about "tipping" as if it was some part of the trip cost, and is deserving for some average level of service ("good")? It isn't. $375 is the cost of the trip. A guide is not a restaurant worker. He doesn't charge you, or pay himself(i.e., minimum wage or less), like a restaurant worker. Accordingly, there are no percentages like a restaurant worker. It is not 5%, or 10%, or 20%, or any such percent. The guide should do his job for the $375.
If you feel like tipping, do so in any amount you feel is appropriate. Guides that scowl and shrug at clients' $20 tips should just give them back, and consider moving on to another line of work.
I advise that you tip if it is truely deserved, and that means much better than "good" or "average" service. Good service is worth $375, not more.
...another perspective on tipping
I've followed the threads on tipping....and this is by all means not an attempt to justify or persuade why a client should tip....that is totally up to the client.
I'd like to make comments relative to shop guides vs independent guides (such as myself). People have mentioned (such as Fats above) that the shop guide gets $$$ taken off the top and does not receive the full fee paid the shop or outfitter...so therefore a tip is considered & merited. That is true.
It is a false assumption that an independent guide receives the full amount of the fee he/she receives when you consider they have operational expenses that a shop or outfitter guide may not; both fixed and variable. Such expenses, whether pro-rated or actual daily costs (such as flies, lunches, leaders...assuming there is no charge and part of the fee) are: liability insurance, fees paid to the USFS or other agencies, advertising, business phone, website expenses, shows, wear & tear on wading gear that has to be replaced (at least one broken rod per year), to mention a few.
Again, tipping is totally up to the client. I just want to clarify that independents do have expenses that "stabled" guides may not. Very possibly equal to the amount of the shop guide's fee deduction. As to fee deduction, I'm aware of as low as 20% and high as 40%. Personally I feel the high % may be pushing the envelop...but who am I say since I don't run a shop or am an outfitter.
Frank R. Pisciotta