个 ge usage plus 每 mei Anybody can explain me the reason why:
-we don't say 每个年 but 每年? and, on the contrary,
we must say 每个月 and not 每月?
-Is there somethig to do with the fact that sometimes we must use 全 (全身)instead of 整个 while we must say 整个身体 and don't 全身体?
Thanks (Húli)
PS/Afterwards I have introduced some changes on my previous post in order to clarify it.
The reason is that 天, 日, 周, 年 are themselves counter words / classifiers (so they don't need an extra one), while 星期, 礼拜, 月 are not classifiers and therefore require a classifier, which happen to be 个 for the all of them.

Note that although 月 is listed with the ones that require a classifier, it's quite frequent to hear 每月 as well (which I believe makes sense since we already have a classifier for day, week and year).