Yeah. Heck, even with calc games we do this sometimes. In Metroid II: Evolution, certain map data is used several times in a row, for example if you fall in a huge pit. In Illusiat 13, if I didn't do that with the Desert and the 4th Dimension dungeon, the game wouldn't even fit on a regular 83+ if it ever got finished.

In some old Illusiat games, the same map data was used for multiple dungeons too. For example, in Illusiat 11, the fire, ice and bolt dungeons are identical except the ASCII sprite palettes (which contains 2 tiles for the dungeon, 1 for the battle floor and one for the event triggering tile) were not the same accross all 3 dungeons. In Illusiat 10, there are twin towers somewhere. One is the magic tower and the other is the strenght tower. Both are exactly the same, even the tile palettes. Fortunately the entire game is not like this so only certain parts can be repetitive. Also those dungeons are generally very small (1x8 rooms, usually). This is always done to save space and stuff, not really because of laziness. Sometimes the limitations at the time are just too much.

Oh for example, my maps are split by columns. Each subprogram containing map data contains one column. If there's a huge pit somewhere, instead of doing

If A=1
map data
If A=2
map data
If A=3
map data
If A=4
map data
If A=5
map data
...
If A=20
map data
If A=21
map data

If for example the repetitive maps ranges from row 2 through 5 (row being A), I'll do the following instead:

If A=1
map data
If A>1 and A<6
map data
...
If A=20
map data
If A=21
map data

Saving a lot of memory

And yeah what you say about infinite corridors is how they works. I think some of my games uses such method. Instead of moving one map forward it just loops back.

Woah read time stamps bro, it's almost been 2 years since the last post here.

Wow quite the necropost indeed. I guess it doesn't help that this forum section barely has any discussion, though. X.x