How do you (or how does your favorite system) handle dungeon evacuations? Why is this your preferred method?

Sometimes, the party has to leave the dungeon before they’ve completely explored it, satisfied their objective therein, etc. Alternatively, the party has “finished” the dungeon and either they (or the GM) does not want to backtrack through all the rooms they’ve just cleared, instead “evacuating” (whether to the dungeon entrance or even back to town) instantaneously.

In either case, TTRPG groups/systems may have some designated mechanic or procedure (sometimes called an escape roll, sometimes not) for allowing the party to leave the dungeon without actually having to backtrack. Some megadungeons are even designed with the idea that parties will end each session back in town, no matter where/when their dungeoneering for the day has concluded.

My question to you is, how do you (or your group) or your preferred system go about handling the “leave the dungeon” bits of play? Why is this the mechanic/procedure you prefer and/or have come to rely on?