As a host or as a guest?

4 weeks is too little for me because I'd lose too much time to travel, especially if I have some gigs in the middle, so for me, 4-5 weeks is the exception... twice a year maybe as a bridging solution. I've personally found that 3x3 months and then some time between them filled with a vacay, and some gig work where I don't have a base and kindly request to dump my suitcase with family or friends for a few weeks works best.