Temporary vs Permanent Gains

What PE practices give the most PERMANENT gains vs TEMPORARY gains. I’m thinking of hanging, pumping, clamping, and jelqing. Are pumping gains the most temporary? Are length gains from hanging the most permanent? If you gained an inch from hanging then stopped cold turkey, would there be rebound. Would you lose some length? I’d guess that girth and vascularity gains from clamping would be very permanent. Reading threads over the years, it seems like every big gainer once they totally stop PE, loses a very small fraction of their gains. Have you done PE for a long time, made significant gains, stopped PE, and then lost a percent of those gains?