I rarely update my Garmin 2797, the roads around here have not disappeared, the only "problem" I noted when I went up to Dayton, OH last month, was that construction caused some detours.
But, the 2797 has the "live Traffic" feature, and when I would get into St. Louis it started talking to me and changing my route.
Same thing happened a year ago March when I went through Birmingham, AL. I was on Mississippi 78 and wanted to turn east on I-20.... which happens to be under construction still yet.
The 2797 started telling me about 10 miles in advance that there are detours to my route, to just follow the turn-by-turn instructions.... got really tight in a couple of places.... I was pulling our Toy hauler and the 'new detour' took us on downtown narrow streets... I had to do some wild cross over the center line moves to keep the from climbing over the curbs. but, it only cost us about 10 minutes. not too bad.