I've heard that too, 'Strang.12 string said:Don't know if this is true, but I have heard it said that leaving a neck without tension for a long time risks a permanent and incurable back bow.
Back to the OP, I guess we just don't know how long our guitars will last. My oldest guitar is a mid-forties Gibson Banner Headstock J-45. In its seventh decade it still performs beautifully, and as has been pointed out, many forum members have older instruments. I'm confident that all of my guitars will outlast me...
' Strang
I made a comment about the guitar neck earlier in this thread that seemed to spark much of this conversation (sorry I've been offline for a few days)... I think the only thing I have to add is that I have seen some guitars that have needed resets because of neck geometry changes over time (whether due to neck block shifting or neck bowing). I've seen others that haven't (in 30+ years) and are as correct as they were built.
I don't know if it's a guarantee that all necks will need adjustment over time. Perhaps not, although I suspect in 300 years there will be no guitars from the 20th century that are still playable without having undergone extensive repair (as already discussed in this thread). I guess my only point was that, with respect to guitar longevity, the neck is a factor, even in the short-term, that shouldn't be overlooked. To me, it seems the neck is one of the "weak points" in this regard, as is (probably) the soundboard. And, no, I'm not actually citing any published material; I'm just stating my observation.