There was a poll on this subject but it only had 14 response and is a couple of years old so I thought I'd repost the poll to get more current timings.

How much time in the VPC alternate universe?
1 to 7 days
8 to 14
15 to 21
22 to 28
29 to 35
36 to 42
43 to 49
50 to 56
57 to 63
63+ days