This could be done, but I wouldn’t recommend it.
There’s one small study where men with low fertility took Clomid Clomiphene Citrate at 100 mg/day for a year, and they had good results and no problems. So it’s not that there’s no medical evidence at all for somewhat long term Clomid use, but it’s very limited.
There have been many women who have taken Nolvadex Tamoxifen continuously for years, and there was a period where doctors were prescribing it as a prophylactic for women who were at inherited risk for breast cancer.
However, more caution is being applied to that use now, because Nolvadex is very slightly carcinogenic itself, as is Clomid. And so it becomes a benefit to risk question.
For standard PCT use, the exposure is fairly limited, only a relatively few weeks per year. There’s probably more risk of dying from a coconut hitting you in the head than from using Clomid or Nolvadex for PCT. And the benefit, proper HPTA recovery, is very considerable. So I strongly feel that the risk-benefit equation works out for this use.
However, using either of these drugs 52 weeks per year for decades on end would cause far more exposure, and there would be absolutely no benefit that can’t instead be achieved with ongoing HCG use and control of estradiol level with an antiaromatase, or often even only with an antiaromatase. I wouldn’t use a SERM chronically.