That is your decision in coordination with your medical team...

Generally, the Lupron injections can be 1, 3 or 6 months.

Choosing which one can be a function of several things:

1. Your ability to get to your doctor's office for the injection - health, distance, transportation.
2. Whether or not you want some degree of flexibility should you decide to stop, if yes, one month, if no, six months
3. Financial toxicity - besides the cost of the drug, there are various other administration costs associated with the nurse and doctor who are involved.

Others may chime in with their experience when they were on Lupron. I was on it for 18 months, Jan 17-May, 18, chose the 90 day shots in part for reason 2 as it turned out our original plan was 24 months but we stopped at 18 given my response, PSA undetectable with the first injection and stayed there.

My time on these forums during the ten years of my journey doesn't show a "difference" in the side affects between the shots or recovery once it clears, a lot of anecdotal comments so I didn't include that as #4.

You didn't summarize your treatment history so the forum members can't provide input on your treatment. I will say that mono-therapy for recurrence is generally out of date, some combination of doublet or triplet therapy may be in order, depends on your clinical data.

There is an oral alternative, Orgovyx which has advantages over Lupron:
No Flare
Faster castration
Higher sustained castration
Lower CV side effect profile
Faster recovery of T if you recover) once stopping.

It can be expensive, depends on your insurance.

Kevin