Latter 40's, married with a 3 year old fireball of a daughter, live way inland, kinda hard to get away from work and taking about 4 weeks/year vacation, I plan for 1 family week (typically a cruise), 1 week with my parents & grandmother out-of-state, 1 week solo dedicated dive vacation (20 to 28 dives) & a 1 week 'scuba trip discussed as a family vacation' (as my wife aptly calls it) aiming for 10 dives.
This year's a little atypical, but the above is the very rough model for how I look at a year. Plus a very few dives at the local quarry to try new gear, 'stay wet' once in awhile, etc...
So I'd say about 35 - 40 dives.
If you're childless or an empty nester married to a fellow dive-aholic and have a good income or live in a prime location (e.g.: near Florida Keys), your situation is very different. What's realistic is different. My planned annual dive count is modest, but I give up considerable potential time with my parents & grandmother (she's very old & medically compromised so they're not mobile, and they live a good way off) to go do, oh, say, a live-aboard. But my passions enrich my life & encourage me to keep plugging, give me something to pour my interest into, so I think that has value, too.
Richard.