There was a time when some of my gut customers would break a gut string early, or when they take it out of the tennis bag later.
Usually what happens is they shank a ball (mishit) , and stresses the string at the grommet area, and later breaks in bag.
last few years I have been applying a lube at the main string grommet areas (I use Tri Flow) using a small round micro fiber brush, and I no longer see those early breaks. Only downside is needing to clean clamps real well after job is done .I gave this idea to the USRSA a while back and they published it in their magazine.
Gut is a fragile string and when string is against grommet for a while it is like glued into the grommet and when stressed or dries out it can snap right at a grommet area. Have you sometimes when you remove old strings from a racquet it is really secure into a grommet and you really need to pull hard to remove it almost like it fused to the grommet, so if a mishit was against a string as such there would be no give at the grommet area, it cannot tolerate the force and snap at even a later date, or can snap at that grommet because of the stress against grommet as string dries out with nat. gut.Try the lube with nat. gut next time.It does not take much, just a small drop on a tiny micro brush and spin it through the grommet openings before you string it.It will keep the string lubed at that vulnerable spot and help with mishits as well. I only use that with the nat. gut hitters. It takes a little more time to apply and later clean machine well, so charge accordingly.