@WearyAuldWumman yes it can be a bother getting the weights you want! At most gyms there's sort of big boy range starting at maybe 5 or 7.5 kg, going up by 2.5 then 5kg, up to 35-50kg depending on the gym. And there's often a small rack somewhere with pairs starting at 0.5 or 1, going up by 1kg to 10. And then somewhere else, maybe in a studio or in a corner, there will be a whole pile of 1.5/2/3/4 kg weights for classes. And then there are kettle bells which tend to start at 4 and go up in even numbers. The smaller kettle bells tend to gather dust, and there's often a few of them. Not to forget the smaller weight plates. These start at 1.25kg usually and you can find 1.25/2.5/5 easily in any gym - and if there's a studio there's probably loads of them for body pump type classes.
So all of that said, if you can't get the exact weight you want, but you can get a kettlebell or a slightly different dumbell, you're already winning. For most basic purposes a kettlebell or a plate and a dumbell are interchangable, just a slightly different grip.
If you can't get exactly the weight you want, but get +1 kg, then you can do like a regressed version or lower reps. and if you can get a -1kg weight, then do more reps or more sets.
And if you can't find any weights at all, a lot of things can be done with the rubber bands, if you know what exercise to do. And there's usually a bunch of bands gathering dust somewhere.
I hope some of that helps, because we all know the pain of not being able to get the exact thing we want when we want it, during limited time at the gym!