Too many variables in this game, but there are averages. Average seems to be if you get one transplant, odds are you will need another at some point down the road. Especially if you're younger. A lot also depends on how proactive you are in protecting the hair you have. As to why you don't see updates years and years after? Well personally I think the people happy with their results want to put this behind them and those unhappy give up/move on. I've seen a few logs 5-10 years after where the person maintained what they got and logs where they ended up big time regretting it. My advice would be to act conservatively if you decide to move forward.