I paused my guiding career 20 years ago and am looking to get back in again. Tips went from 0, to over 100% of trip price. As Mr. Stewart pointed out there are many factors, but it primarily comes down to the clients' views on tipping.
Trust me I'm cheap, 1 haircut=a set of clippers that does the job for years.
As a former guide tipping is something I don't skimp on(client view). When you find a great guide, you have found an entire network.
What client gets called when a cancellation comes up, and it's going to be epic?
Who can find another boat, bait supplier, launch, guide-if something drastic happens?
Who knows great guides and great locations if you are going someplace else?
The best guides I know often shake hands and book it up again a year out, and both parties are looking forward to it, no matter what the fishing is.
My $0.02