This was an interesting thread to read. I've often wondered how I might have progressed had I not divided my focus into so many guitars and different aspects to music. I was, and still am intoxicated by all things music. But what if I was not? I can certainly hyper-focus with the best of them. I can also jump from topic to topic with the best of them. In the case of music, it is that I am an insatiable learner.
That is where my buying and keeping habits begin. I buy a guitar type to learn how to add a particular sonic attribute or skill to my skill-set. As I grew, I replaced the gear for the aspects of music that most interested me as they happened. Do I sell the old? Only if I do not like it. I sold a Taylor 314 to help fund my Hummingbird. I did not sell a Squire Affinity Tele to help fund the USA Tele.
The one time I did sell gear that I liked and functioned well in order to get that next sound was when I sold a low-mid range Ibanez metal type guitar with non-active pickups. It was a $400 guitar. I was no longer trying to play the type of music it was great at. I've since wished I had kept it, though it's never been a strong enough sentiment in me to actually replace it directly. Still, that was the last time I sold a guitar because I migrated to the next thing.
That said, I've learned that I will almost always re-visit a particular topic as if it were some revolving door. Years will pass sometimes between learning something once and doing it again. Especially when I make music as eclectic as my listening tastes are(originals and covers).
That does not explain why I keep that Squire Affinity Tele, though.