It's incredibly simple.
If you are happy with the maps you already have on you device, that your carefully prepared routes display correctly, that you'll be able to use the device just as you expect you should whilst you are away on your epic Adventure (with a capital A) then leave it as it is; forever if necessary.
If you feel like updating your device before you go, do it; though risk losing what you've already got and are happy with.
If, after an unsuccessful update, your holiday is at risk, then decide if you are still prepared to go and / or work to cure the problem, using the various fixes described in assorted posts on this site and others.
If you decide to leave it as it is until after you come back, see above.
In short: Do it or don't. It's your urge, your device, your holiday, your life. Nobody but you cares what you do.