If your LD is 1 week long, but it is only 1 IRL hour. Does it feel like one hour or one week?
There aren’t many cases that I know of where people had week long dreams… but if that was the case then the dream would feel as long as you ‘feel’ it was. When you wake up you can only estimate how long the LD actually lasted for.
I’ve done this before, as i thought it would be a way to extend my LDing time.
My answer is that if you have a lucid dream that lasts for a week in your head, it will feel as long as any other dream (much to my dismay).
I’m not sure because I haven’t been able to prolong a LD yet, but you might want to drop WritersCube a question — he’s had week- and even month-long LDs. I should think that they would feel as long as they last in your head, though.
Well, aren’t we supposed to have like a lot of dreams per night but we just don’t experience all of them? I guess our brain can generate dreams very quickly. And I believe that dream time is different than real time in that we can absorb these dreams in a very small amount of time (say an hour in the proposed case above).
(If that makes any sense, haha)
We don’t remember all the dreams. We have a lot more of them in the night than we often remember. But we do experience all of them, how else could you dream them? 
To answer the first posters question, it can differ. It very much depends on the dream I think. If your LD is a week long it often, if not always, means that you skipped some points. If you look at a movie sometimes it can take up to 10 years, but the movie doesn’t last 10 years, neither does it feel like it lasted 10 years. That’s because you don’t see everything, so if you have a LD from a week, I think it would be the same.
Try to think of dreams as memories - You’re brain can come up with a false memory about you living in africa for a whole year which makes it possible for you to tell detailed stuff about days and events in less than an hour, simply shift between different stuff (from what you did on the airport till the day you went home).
So basicly you can “create” more time, since it’s all in your head.
(hope you understood me 
)
Sometimes I have dreams when I’m like “I CANT BELIEVE I JUST SPENT 9 HOURS AFTER SCHOOL!”, it feels like 9 hours in the dream, but once you wake up it doesn’t feel long. I can’t remember where, but I read something about a man who experienced 100 years in his dream, I bet he wouldn’t want to go to work the next day
As MovieMe points it out, you can have false memories in dreams, that make you believe there was a long “past”. It’s also possible to have ellipses in dreams, or sort of off-voices that are summarizing long events, like in movies. Most of the dreams that give the feeling of being weeks long are made so. Now generally, LD’s and ND’s are in real time, and the feeling of dream time is not so different from real time.
For instance, there was an experiment leaded by Pr Dement - LaBerge’s teacher - in which he woke up dreamers five minutes, or ten minutes, or twenty minutes after the beginning of REM sleep, and the dream account duration corresponded to the REM sleep duration. As for LaBerge’s, he made an experiment in which LD’ers were counting 10 seconds in LD’s, and the dream time was the same than the real time.
I have had a few several hour long dreams, that weren’t that long in real life. In extreme cases though, it does indeed feel like I’ve stayed up all night. Not tired, but feeling like it has indeed been at least 8 hours since I went to bed. Mostly depends on the vividness of the dream I guess.