This kinda thing varies for man to man lah. For my case so far depend on 2 factors, sex partner & aging.
Unlike in my younger days, now m usually max 1 shot a day. During my teens to early 30's ammo was almost like unlimited, record was 6 shots a nite (~6hr) there was once a short 4day 3nite trip up north my gf & me was humping like mad 4~6 shots daily after which we like avoided sex for almost a week. Through mid-late 30's thing started going downhill, can get 3shots a nite very happy liao. Until ~2yrs back sometime with correct partner & setting still can do atleast 2 consecutive shots humping non stop over an he but nowadays sight...old liao. Even with new syt partners also take >2hr to ready 2rd. Few mths back brought my 19yo fb to sentosa & I only manage 1shot after checking into Shang @2pm, 2nd shot ~11pm & 3rd shot b4 check out @12pm next day. In-between them I was limp, can hardly have any erection even when she tried bbbj me during shower
With wife, now usually 1 shot per day/days. Sometime if the setting is rite, may go for 2rd but I may not cum, just stay erected to satisfy her, sometime deploying my reserve force, my most trusted fingers. So to avoid an unsextify wife, I will always vary my style & speed holding my shot till she has a cum or 2 b4 I go for the kill.