Another one I did is figuring out that €25 is 50k sats. (25*2*1000). That's my "should probably pull it into LN self-custody" level. And 100k sats is then €50 and that's my "should probably pull it into hard wallet" level. 

 I just picked €25 because that seemed like a pain point. That's a dinner at a restaurant or a steak from my butcher. Half a tank of gas.