I do a hill training class each Tuesday night. You can pick out the old timers, like myself and my buddies and the newbies, strong but inexperienced riders.
The oldsters know to get down into granny and set up a regular steady cadence. I basically can ride up a tough 14% 1 mile hill, slow, but in control and not out of breath. The newbies try to power it up and quickly run out of stream. We play Tortoise and hare all the way up. The big difference is when we crest, I'm feeling good and can power on and the newbie is still out of stream and having to stop and catch their breathe.
If the hill is short, then I have no problem powering up and but if there is any distance, then I learned, through my mountain bike training, to use hills to rest, use the proper gearing, keep a steady stroke, keep breathing under control, feel good after.
My mountain bike friends taught me to go into a low gear and then once you catch a steady rhythm, gear up. Better than trying a hard gear and than having to go down.
PS: Last Tuesday's class I did 17.9 miles and 1835' of climbing.