A regular to me is, someone I see on a regular basis... Ie once or twice a week, month etc, not after their 3rd visit. Bloody hell if someone came 3 times in 12 months I probably wouldn't even register them

One guy has been every week (bar illness and holidays) for 15 years, now i call him a regular

When I first started years ago I remember being really surprised having men return again and again, as I thought the whole point and excitement was to see someone new.
I think for some it takes a while to get comfortable with your persona/offering etc and then you'll start to notice them, not sure it's a matter of time for everyone.
As LL says if your getting clients I wouldn't worry