1. The seal in my 3240 was leaking when I bought it, and over the course of another 40 hours of use it slowly got worse. Eventually it was losing about a quart every couple of hours, and that's when I decided to fix it, but I didn't feel like I was in any hurry. It was mostly a cosmetic issue, but the hydraulic fluid isn't cheap either, and I couldn't park the tractor on concrete without leaving behind a mess. I also didn't want the thing to get a lot worse in the middle of a job that I couldn't afford to stop, so over the Christmas holiday I started in on the repair and had it done early in the new year. Not much fun working in a cold garage, but cold was still 40F and not really that bad.
2. As mentioned in my previous post, I decided to fix it myself. I'm retired, and these days I have more time than money. The dealership was very nice about giving access to their mechanic, and in helping get the parts ordered, so we both benefited. Faced with the same situation, I wouldn't hesitate to do it again the same way.
3. That's a better estimate than I got. It probably took me double the amount of hours, but I'd never done that job before, and I spent a lot of time cleaning parts prior to reassembly and fixing other problems I discovered along the way. I also made some mistakes that cost me delays caused by having to order parts I damaged during disassembly. Even with that, though, I was able to do the job for about 1/10 the estimated cost. That in itself was worth it to me, and now I feel like I know a lot more about the machine, and have more confidence in my ability to fix it should the occasion arise again (and as under engineered as these things are, I'm sure I will).