For the fun of it and in order to master the system, I like to make my NPC's as real player characters with the excel character sheet, and making them plausible. I use a general rule of thumb in my game world that an NPC will level about every two years once they have reached the age of 15-20 (depending on biography) and can be called adult. That means sorcerors in their late 50s will usually hit level 20, and if I have a 100 year old cleric, well, you can do the math.
I just made such a cleric who used to be a fisherman's daughter, and was trained to be a magical healer only after she reached level 2. Her whole biography is reflected in what she learned when (which the excel character sheet makes good record of, really, this piece of bytes is just an awesome play aid). She learned carefully, usually only one rank per level per skill, to make the most out of her time, and still couldn't learn everything that would have been optimal. Instead, she had to make tough choices and postpone some things to later, and some things she never got to learn despite the initial intention to do so. She still hasn't learned any weapon skill, for example (and at 104 years of age, she'll probably not do it before she dies).
What I noticed is that even at extremely high levels, RMU characters will NOT know everything and not excel at all the things there are. They remain… playable, for lack of a better word. I am not sure that is actually BETTER than in previous editions, as my games there usually took place at the lower levels, but it is GOOD.
My current campaign will eventually feature player characters of level 50 or more by design. i am really looking forward to it after having built a few NPC's of levels 17-41. I would suggest: If you have any anxiety about playing RMU at higher levels, let go of it. The characters aren't omnipotent even then, but very diverse in their development. And of course, this is RoleMaster anyway, so character death even against low-level opponents is always on the table... :->
