Its not a problem, and I guess I live in a cold climate.
Some of the newest models now have a gauge showing how much DEF is left. Its not an issue replacing it. Widely available, I usually do the Wally World route and buy it there. Five minutes of work (or less) to refill, and frequency depends on how much you tow heavy and how you drive the vehicle. For my 2011, I suppose every 5000 miles or so I dump some in.
As before, no gauge on my 2011. But there is a place to see if it is below 1/2 tank full within the information center on my dash. So I check there every once in a while, and if below 1/2, I run by Wally World and get more.