I’ve modified backpacks, tents, clothes, stoves, etc. since the ’70s and am still at it.
Gear I use often “needs” modification to suit my personal requirements like a stronger, more wind-resistant tent, a better zipper baffle in my -30 F. parka, an entire flat aluminum stay frame added to a wimpy “frame sheet”, etc. And so far I’ve always made the gear better, at least IMHO.
The first symptom of this affliction was in the late ’70s and usually as I was lying awake under my tarp  before dreamland. Thoughts of how I wanted to change this or that with my backpacking gear would pop into my head. At first I ignored these ideas upon returning home but then on the next trip, yep, same ideas plus a few more made me realize I’d better “improve” my gear.
So I scratched the itch and began modifying. A North Face Ruthsac, one of the first internal frame backpacks and first project, was modified by turning a single compartment, zip open pac to a two compartment pack with a zip open divider between them just in case I still needed one large compartment.
So, while having made only a few things like knee high gaiters and  two pouches, my list of modded gear constantly grows. The modded items I’ve sold were very well received by the buyers so I guess I do know “a thing or two”.
I remember my first Tarptent Moment was a single wall tent. I wanted to run the crossing pole under the fly for more support. Henry Shires said it couldn’t be done B/C the poles would be stopped by the netting at each end. So I sewed a Velcro strip to the netting at each end, melted a hole for the X-ing pole through the Velcro and sewed a mating Velcro strip at its top end to the first Velcro strip so it would close the hole for the X-ing pole.
Worked like a charm and the guy that bought it liked to too as it also made the tent free standing.
