Hello from the Pacific Northwest! The beer I have in primary downstairs was pitched with the yeast from the beer I now have in my secondary! I brew all glass, and I have three 5-gallon carboys. I'm no expert at washing, I just watched a video on YouTube and gave it a shot. No sanitizing tertiary vessels, no refrigeration, low risk of infection.
I racked one beer to secondary and locked it up.
I brought the old primary carboy upstairs, hit it with some clean water, swished it, and laid the carboy on its side, propped by towels.
I boiled a new wort, cooled it, transferred it to primary, aerated, and dumped the top yeast layer from the first vessel right into the new beer. The fermentation is crazy active. It was originally a double-pitch of San Diego Super Yeast. Cost me like $18 USD. Better believe I'm learning how to harvest at that cost. I'm going to continue to re-pitch until I sense something funny, and then I was going to go a bit cheaper with the next round, either US-05 or Bry-97.