That really depends on the person... many people have several hours of REM each night in fairly long blocks.
I average 2.5 hours of REM/night (measured via ZEO), and apparently 2 hours/night is average for demographic of men aged 17-29 (per ZEOs user stats).
I typically have at least one solid non-fragmented hour long block, and a second block of at least 30 minutes with the remaining hour from small blocks.
So, transferable skills: skills that, upon improvement, increase your ability in other areas (and also improve other, higher-level skills).
A basic example would be reading/writing. Knowing how to read and write allows one to access a huge amount of other skills and resources which are otherwise unavailable. A less obvious example would be clear speech (enunciation). Ability to speak clearly improves one's prospects in a lot of different areas (e.g. professional advancement, dating, etc.).
I'm looking for additional examples. Which skills did you find to be most transferable? Did you become proficient in X, and then found this helped you in many other areas of your life? Please share.
(I tried to find whether this was discussed before, and failed; if it was, I would appreciate the link.)