This achievement requires that you play games for 36 hours. You can obviously just play games for 36 hours, but I used an alternate method for this that also gets me the gold time spender medal, as I didn't accumulate 36 hours earning all the survivor and points gold medals I needed, leaving me with just time spenders.
The way I did this was using a turbo controller. Enter the classic mode (not ranked) of just about any game and then turn turbo on for the left trigger (the rewind button). I used a Horipad X-2 turbo controller for this, although I don't think it matters. This will result in the game slowly rewinding until it rewinds as far as it can, and then it will move forward half a second, rewind back, and then repeat the process again and again. Since the game can't end, you never have to worry about the timer stopping or the game idling out. I leave it on when I go to work, go to sleep, hang out with friends, whatever.
You can switch games as you like to get gold time spenders medals, or you can leave it on one game for 36 hours if you like. It's cumulative across games and playing sessions so any combination will work. Achievement will pop whenever you've hit the 36 hour mark and you don't need to end the game to get it, so it will probably pop sometime while you are at work/school etc, so make sure it's connected to live if you want a timestamp.
A small fraction of the games won't allow you to do this because they freeze too damn often. Super Breakout and Battleanis froze night after night when I left them on turbo and I had to do them manually. Your experience may differ. As I said, it's only a fraction, as I had 27 games total and only 2 were crashing.