I go through phases with practice. I do none for months at a time and then, for some unknown reason, I start practising again. LMM's posts about her old Bechstein have prompted me to start again. I'll probably keep it up for a few weeks and then forget about it.
Sadly, although I have shelves full of wonderful music, I always seem to gravitate towards the same pieces. I played the rondo from the Pathetique for my Grade 7 in 1971, played the whole sonata from memory for my LGSM in 1981 and I don't think I've learned another sonata since. Of the 32 that old Ludwig wrote, I think I've only ever learned 4 or 5.
I'm actually surprised how quickly I can get up to a reasonable standard on pieces I used to know well - unless my ear is now more easily satisfied with a throughly mediocre performance than it used to be! A couple of hours' practise and my hands are finding the notes again, although as you say, the agility takes longer to come back.