A partial answer to your question may be possible, but I have not run across a simple answer. I too would like to have a time line to help in the "what next" decision making process.
Dr. Lamm, and others, in a consensus document (link below) suggest that in the range of one and one-half to two years after high grade cancer is detected and remains non-responsive to treatment, it is time to consider all options. the goal then being to avoid increasing risk of invasion.
That statement is the closest I have seen to a timeline for bladder cancer. The full article is at:
6/2015 HG Papillary & CIS
3 Years and 30 BCG/BCG+Inf
Tis CIS comes back.
BC clear as of 5/17 !
RCC found in my one & only kidney 10/17
Begin Chemo; Cisplatin and Gemzar
8/18 begin Chemo# 3
Begin year 4 with cis
2/19 Chemo #4
9/19 NED again
1/2020 CIS is back
Tried Keytruda, stopped by side effects
Workin on a new plan for 2021