Kidneys are amazing -- filtering blood, removing excess liquid, regulating blood pressure. And they're redundant! My brother lost one kidney in an accident that also left him paralyzed and with a slew of other problems. Recurring UTI and kidney infections took the other kidney a decade later. When he started on dialysis around 1988, the machine was the size of an Asteroids arcade game. It did half the job of a fist-sized kidney maybe half as well. A few years later, we had a home machine a bit smaller than Asteroids. In 1994, I gave him one of mine (kidneys, not arcade games).
The doctors said if the transplant lasted 10 years, we should be delighted, especially with all his post-accident reconfigured internals. My brother's quality-of-life improved immediately — at least he didn't have to be hooked up to a machine and stationary for several hours at a time. My quality of life was essentially unchanged. The transplant worked well for 22 years. Recurring infections -- kidney, liver, bedsores, staph/mercer -- eventually took their toll. I'm pretty sure I wouldn't have done it for "my stepfather's brother" or the like, but I'm glad I did what I could for my brother when I did. I was 23 at the time and now 46. I drink plenty of liquids. My GP's a nephrologist and I have kidney function tests as part of my annual bloodwork. Maybe I'll be pissed if shit goes wrong as I age. With hope I'm still glad I did what I could when I did. And, with hope, the redundancy remains very good.