35 minutes may be a bit much
I have timed them several times.
I had one anal customer, that once her 40 yo faucet had been replaced, then expected instant water shutoff on the new fixture.
I started keeping track of time, how long tubs would take to finally quit dripping after shutoff.
Average time, if your anal customer is hanging out in the bathroom watching the tub spout, 35 minutes.
What the heck is wrong with watching "The Price is Right"?
Why do they grab a chair and watch the tub spout?
Forget about it.
The water is off.
It takes that long to become bone dry inside all those pipes in the wall.
That's why, when I shut off water for a plumbing repair, I open up every faucet in the home, starting at the top.
If they have four bathrooms, I go into four bathrooms and start opening faucets.
The quicker all that water can finish sliding out of the pipes, the sooner I can start soldering the new joint.
You can't solder if water continues to drip for hours.
And you other plumbers, don't you love it when the HO tells you over the phone that you can cut, install a fitting and solder in 15 minutes.
It takes way longer then that for the water to quit leaking toward the new joint.
With these guys, I tell them to keep looking.
I'm pretty fast, but you can't beat nature.