So what's your biggest mistake you have made so far as a beekeeper.
For me I'd have to say open feeding my nucs in the nuc yard in mid summer .
I had all the bees on my 12 acres come to the feeder then after 2 days started robbing everything in site {13 nucs} it look like a alfred Hitchcock movie . Took me the rest of the year to get them back up to weight and still some felt lite going in to winter. And I have to move my nuc yard away from the house now to keep the peace with the wife she was not real happy with that many PO bees.