Actually birding - going out with the intention of searching for birds in order to observe their behaviour or identify them. If you wear glasses and if your objective is first and foremost to find birds, you are at a handicap if you cannot seamlessly bring your binoculars to your eyes (for instance - because you have to remove glasses first), as even if you are pretty slick with the glasses-removal procedure, some birds will have vanished by then.
I sometimes choose one of my older binoculars with short eye relief, for reasons such as field of view - but take care to use them where their disadvantages are mitigated as much as possible (ie. where I'll be "in the binoculars" virtually all the time). But I've been wrong-footed a fair number of times - either not being quick enough to get on a bird, or not even knowing it was there.
Of course if there's no risk that your targets will fly or move away, or if you just want to use a particular binocular for nostalgia or other reasons (which I do sometimes), your considerations will be different - in which case, do what pleases you.