Things take longer than you think they're going to, as a rule. There is the odd exception, tasks you've been putting off for so long they assume an almost insurmountable psychological difficulty, until eventually circumstances force you to get on with them and you find they barely take ten minutes. But as a rule things take longer than you think.
Take the beehive supers. I had a spare super with no frames in it. I thought I would get some frames in case I needed to use the super, so ordered them, only to notice after they had arrived that the super was missing the metal frame spacers that are supposed to go along the top of each side, and that I didn't have a spare set of spacers in my box of beekeeping bits. I don't know why it didn't have any spacers. Maybe it used to have plastic ones and I removed them so that I could clean it. It didn't look as though it had ever felt the blowlamp's kiss, in fact it looked unused, so probably it was one of a set I bought a couple of years ago from a cheap and useful US beekeeping supplies firm which, alas, abandoned its attempt to break into the UK market even before Brexit sent sterling plummeting. In that case it may never have had spacers, since they wouldn't have come as part of the budget kit.
So I had to send off for spacers, which was a bore because if I'd noticed in time they could have shared the delivery charge with the frames. This morning I made up the frames, a job I should obviously have done in the winter ready for the season ahead if only I'd been better organised and had fewer colds. Then I found that the metal spacer would not fit properly along one side of the super because in assembling the box I had banged a nail in about three millimeters higher than it should have been, and the nail was now obstructing the narrow slit the metal spacer bar had to fit into.
I tried to pull the nail out with a pair of pliers, but without success, even after I'd squashed the grain of the surrounding wood to try and get a better grip. I had to appeal to the Systems Administrator for help, who tried doing what I'd been doing but with a different pair of pliers and then a small mole grip. The nail refused to budge. The SA eyed up the joints of the box and asked if they had just been glued and I said no, I'd assembled it about two years ago. The SA fetched a third tool, which was a small saw with a blade narrow enough to fit into the slit, and sawed through the nail, which had been on my list of techniques to try, only I didn't have a saw.
Finally about two hours after starting I had a box with frames in it in a fit state to be put on the bees if needed. And I'd thought that making up the frames would take no more than fifty minutes at five minutes a frame.