For me it’s taking so long not because of the crooked teeth (they’ve been straight for a while), but rather because of my crossbite. And I am okay with my crossbite; if they can’t fix that, fine. Four years though…yikes! I hope that isn’t me.
I had Invisalign. I think it was the right call for me, although it did become tough to stay motivated to wear the aligners full time toward the end, when I was burnt out on it and already happy with the results.
I am not sure why, but the orthodontist i went to have me these horrible plastic molded clear plastic retainers that fully covered my teeth. My guess is they were a new gimmick at the time where they were “invisible”, but were impractical as they sealed in any bit of food left in your teeth after eating anything. I was out of braces in early high school and i think i made it a year or two into college before giving up on them completely. Besides being gross when i had to wear them 24/7, they slowly lost their fit wearing them at night starting from the back until they became useless.