For partner airlines, that is. First I had Emirates miles to add (which they don't do any more) which took SEVEN months to get fully credited for, along with numerous emails, faxes, and telephone calls. I even got them a nice gold-embossed letterheaded letter from Emirates confirming I was on the flights.
Then I wanted to get LAN miles credited. One flight got credited automatically, the other three weren't. So I sent off the boarding pass stubs. Not enough information, no fare codes, they said (2 months to decide that). So I try to get more information out of LAN. They kindly printed off my ticket for me, but only for 2 out of the 4 flights. Fair enough, I said, the other two flights were quite short. So I send this information off to BA. Two months after that, they finally credit me with ALL the flights - even though they already stated they didn't have enough information for 2 of the flights! Total time 5 months.
So, is 6 months about average for BA to credit partner airlines manually? Why does it take so long? Of course, I had no confirmation that my emails/faxes had been received which would have been nice ("your fax/email has been received and will be processed in due course. Please allow X days for processing").