We definitely profile "dev startup" a lot, it directly impacts team speed and ability to work on the codebase. Dev startup usually includes a majority of "user startup" too, so it helps -- but it's also really easy to overlook stuff like "massive mods/mod dirs" and the like.
Speaking from experience... Once, I was so annoyed at a "startup UI"-related dialog taking way (wayyyy) too long to load. I dropped an expletive into Slack and, not much later, I was guided toward fixing my own ~2 year old mistake. We were scanning some "user-generated files" in a way that worked fine but scaled horribly -- the operation went from multiple seconds down to milliseconds. Ugh.
Speaking from experience... Once, I was so annoyed at a "startup UI"-related dialog taking way (wayyyy) too long to load. I dropped an expletive into Slack and, not much later, I was guided toward fixing my own ~2 year old mistake. We were scanning some "user-generated files" in a way that worked fine but scaled horribly -- the operation went from multiple seconds down to milliseconds. Ugh.