i know liv 52 is a staple for decades now , but i personally am not a huge fan of it. I primarily go to milk thistle, NAC, L-Glutathione reduced. Sure, i use other supplements, herbs like Vit B12, vit b complex, ... which some add to liver health, but the main go-to ones i mentioned above.
Duration? On-cycle with orals, all through the cycle daily. Off cycle, after pct with labs confirming all is good, take a month or 2 off, then back on. I mean you can go year round on liver helath supps, i dont think ive read or seen anything against that.