Hi HKG,
I started off like 30-60min daily....they deflated as soon as I took them off. A couple of months later, I started pumping several hours daily, sometimes straight, sometimes broken up. The swelling retention started gradually, 45min, 1hr,2 hr, etc. Sometimes, when home all day alone, I kept them on almost all day. The actual growth came about 6 months the shape changed, then at 10 monoths I need to up my bra size to D. I think by this time I kept the size, but lost all the fullness overnight. I was pretty consistent for a couple of years, gradually reducing the time needed. Now my growth is permanent, but I try to pump when ever I can to get the fullness back, but the shape and size remains even after not pumping for months. But, when i do pump now, sometimes just an hour daily, they are still gaining additional permanent growth. I go days and up to a week without pumping now, but like to keep going, not to get bigger, but the lift is amazing. My breast stand taller than women with bras on, and they are very firm, but very natural looking--The first couple of years I was concerned about odd shape, but they have settled nicely.
My nipples only hurt when I have a leak, red dots and one nipple hurting always turn out to be leaks for me. I never had any other nipple issues that I hear others talking about, not sure why but grateful, cause the few times I've had a leak, it's very painful!