I do my own bike fitting. At my age (64) with chronic pain and challenges to strength and flexibility from multiple injury collisions, I realized it's up to me to find what works best for my body at any given time. And with age the challenges don't get any easier. My last full skeletal bone scan revealed worsening stenosis throughout my neck (my C1-C2 were fractured in a 2001 wreck when an SUV ran a light and t-boned my compact car). That tends to limit my saddle time and bike fit.
After doing this for awhile I'm aware of pretty much every pesky misfit ergonomic and balance issue. I'll even make adjustments to suit new shorts/bibs and saddles to accommodate small differences in padding thickness and resilience.
It also helped when I noticed Chris Froome continually fiddled with his bike fit during races, including some rather extreme adjustments to saddle height. I'm not sure whether he adjusted the saddle height to suit the stage or to suit how he felt on a particular day. But some days his saddle height seemed more or less normal, while other stages it looked like his knees might hit his chin. But at his peak it worked for him. Of course, he has an odd physique for a cycling, tall and gangly with posture that looks like a pterodactyl swooped down to snatch a bike and join a race.
I've watched several YouTube channels for tips and the best I've found is
Bike Fit Adviser. No hype. Lots of short videos to address specific fit issues.
I'll also set up a video camera to record myself on the indoor trainer, and occasionally even outdoors taking a few passes to check my ergonomics.
With the exception of a couple of indoor trainer sessions, I've been off the bike since October 2021, mostly due to COVID symptoms. An upper respiratory and inner ear inflammation messed up my balance for months and I didn't trust myself on the bike outdoors. Some days I'd get dizzy spells just bending over while seated to tie my shoes, or turning my head too quickly. Although I did continue running on good days, jogging on meh days and walking when nothing else worked. I figured I could find a soft patch of grass to fall on if vertigo struck.
And I've gained 10 lbs since last autumn, partly due to way too much pecan and pumpkin pie over the holidays, partly due to putting on more upper body muscle after changing my workout routine to include more arm and core work. That affects my bike fit as well.
For now I'm resisting the urge to change the fit on my outdoor road bikes until I have a few more hours in. But I feel free to change the fit on the old steel road bike I use on the trainer to suit how I feel that day. So far the only thing that needs changing is the saddle, until I regain my sitbones-of-steel form of old.