We’re having some similar issues and had a retired woodworker/carpenter friend come out last weekend to help us assess our situation and priorities. He said he always tells people to tent every five years and that no one takes the advice. Elsewhere I had read 10, and decided my current place was okay to move into without it (at 6 years currently).
That said, my neighbor recently did some remodeling and they got a look a large areas of the structural wood. She she said there was *some* termite damage but that the timber being used for construction in 1923 is so dense that it really didn’t matter.
My house used to be a twin of hers, but has been remodeled and an addition was put on in the 80s. I worry about the back, for sure.
Out friend said also said we should tear out the clapboard on the south (leaking) wall and replace with stucco, since the southern exposure is murder on the paint and wood.