To the point where if they're notified that your insurance has lapsed, they will warn you to get replacement coverage, or they will and then bill you for it.
I had a not so fun experience with switching insurance providers at about the same time that my bank was about to make the insurance payment out of escrow.
That was something we had to worry about when buying our house.
The house I have is pretty old and the roof had some issues. I obviously was planning on fixing those, but it became a bit of a catch-22 problem; the insurance I was planning on using (cuz I had a discount from my employer) said that they wouldn't insure me until the roof was thoroughly fixed and/or replaced, but I couldn't fix the roof until the deal closed, and the mortgage company wouldn't close the deal until we had insurance. We were afraid we'd have to pay the insane insurance rates from the mortgage company.
Fortunately, after multiple days of shopping, I found one insurance company that agreed to insure me as long as I fixed the roof within 30 days of closing, which I did.
I had a similar issue with buying a house. In the end we just wrote the roof replacement into the contingency of the contract and adjusted the price a bit so both sides paid a little bit into the cost of the new roof. The roof was replaced, we got our insurance, and the house was sold.
I had a not so fun experience with switching insurance providers at about the same time that my bank was about to make the insurance payment out of escrow.