I guess it's a personal thing, many factors, state of mind, personal horniness, £ disposable, whether you are getting anything otherwise, at home etc./pursuing other interests to occupy yourself, enthusiasm to research/arrange/travel to punts and others I've not included?
Personally started punting in earnest abt. 15 yrs ago, when mid-late 40's, after 2-3 odd dalliances in 1970's, now early 60's, have wound it down last couple of yrs, peaked in 2003-2008 with 3-4 punts per month, energy/£ no object at that time!
Now down to 1 sometimes 2 per month, prefer 1 quality/extended session punt occasionally these days as opposed to as regular as previous, also saves £ as semi-retired now work wise
Enjoy while you can!