It is not true that you can remove the frame in a month with LON doing 3.5 cm. Dont mislead people!!! It takes 2-3 months with LON before you can remove the frame.
What don't you get that the purpose of LON for cosmetic LL is to reduce time in frames. After distraction, the frames come out. If your lengthening 3.5 cm at a rate of 1 mm a day with no complications, the frames are on:
Surgery day
+~7 days to recover
+(x amount of millimeter lengthened) In this case 3.5, it would be fair to assume 35-42 days in frames but unwise due to not accounting for complications.
Remove frames/lock nails into bones
Recover for I think 7 days.
Consolidate with nails only.
If your roommate is doing LON and he thinks he will be in frames for 3 months then he is probably lengthening 8 or 9 cm. When he is done distracting he will remove the frames.
That is if he is doing LON.
I am definitely doing LON.