I buy complete tool collections all the time. I've seen every sad story in the book. Career changes, deaths, disability, or just plain hard times. These are what you have to look for if you want to get a good deal on tools. The guy trying to sell his shinny Snap-on double bank for $5k?...I'll pass, thanks.
The last box I bought was from a Jaguar tech, who now fixes buses. He no longer needs his own tools for work. He just sold his house, (empty nester), and was moving to an apartment, so had no room anymore. He was happy to get a decent price.
I've also bought boxes from folks that were in dire straits. My current home box came from a guy like that. He had quit being a diesel tech to become a truck driver, and that wasn't working out too well for him. As he was about to get evicted, if I didn't buy them, he would have had a real problem dealing with a very large toolbox and howhere to put it, and nowhere to live. The $7k I gave him saved his ***.
Both of these guys were sad to see their tools go out the door, but were very happy to see the cash in their hands. No one who's a good mechanic every likes to part with tools, but sometimes it's the only choice when they are not needed for work, and you no longer have a place to keep them. I just try to find these motivated sellers whenever I need inventory for eBay. They are always out there.