Not really much in the way of a good test to just run on a regular basis to detect bladder cancer. At least nothing that is considered to be low cost enough that insurance would cover regular checks (unless or until you actually have bladder cancer).
Please don't assume that it has gone to "worst layer of muscle--maybe beyond". Ask your uro for the details and get your pathology report. It is yours. You paid for it and all you have to do is sign a release.
If your uro says bladder needs to come out, that probably means it is T2 (it COULD be more, but without evidence--why jump to a worse conclusion).
Life without a bladder is a pretty great life. There are options for urinary diversions depending on your particular situation.
If it is T2b or T3 then chemo will probably be in the cards before or after the surgery. It all depends on what is really there and not on what anyone assumes or guesses is there.
You do want to ask the doctor to be specific. Ask if it is T2a or b, or T3, etc.
Some people have found my treatment guide for patients to be helpful. It is something I personally did, not something from ABLCS or any other group. I did vet it with my surgeon and others have printed it out to use when they talk to their doctor.
bladdercancersupport.org/images/Bladder%20Cancer%20Treatment%20Guide%20v4.pdf
The standard treatment for any T2 (even if it is just barely T2) is bladder removal. Many people also get the bladder removed when it is T1 (not into the muscle yet) so your assumption is not necessarily true. It "could" be, but is more likely not correct.
There isn't a way to "know" ahead of time so you didn't do anything wrong. One spot of blood a long time ago isn't something that would trigger anybody to get to a urologist. The past is the past and really doesn't matter. You are where you are now so it is time to focus on that and what needs to be done now.
Get that pathology report and discuss it with your uro so you know the exact stage now. Your doc at NYU will likely want to do another TURBT unless it can already be determined that the bladder has to come out.
One step at a time. It's hard to think that way right now because this is new to you. However, you did have lung cancer before so you have more experience than most in terms of dealing with cancer.
Let us know here what you learn from your uro and what the doc at NYU says. Lot's of folks here with lots of information and experience dealing with bladder cancer.
Mike