extra primary fermentation vs normal

Out of 50+ batches I've made, only 2 have been in primary bucket for more than a week. the first one was from the northern brewer carmelite tripel partial mash kit, which came out awesome- but that was what the recipe called for. the second is a beer i made 2 weeks ago but it's my own recipe. since i moved my brew op to a new place last weekend, i didn't have time to transfer so i left it thinking all should be OK.

What do you think about extending primary fermentation to 2 weeks instead of 1? anyone know what this does to the beer's character if anything?

I've read that some people like to keep it on yeast bed for extra long (3-4 weeks someone wrote- don't know about that one), most have said to transfer after a week, and I even remember reading when i started brewing that the longer a beer is in contact with the spent grain and yeast on the bottom of the bucket, the more chance for off flavors.

please weigh in.

I really don't think there is a need to keep beer on yeast for 4 weeks if its done fermenting and cleared after 2-3 weeks, but I do notice how much beers improve around week 5-6 since brew day. Where you leave them on yeast or in keg is up to you. I have only 3 kegs so I rather keep my 4 carboys occupied, thus longer primaries for me.

Secondary fermentations are starting to be considered "old school" practice. The idea that keeping beer on the yeast will create off flavors comes from a time when quality yeast was hard to find. If you buy healthy yeast, and practice sanitary brewing, beer will improve with longer primary fermentations. This is because it gives the yeast time to clean up some off flavors produced during fermentation, such as diacetyl. I do a 3-4 week primary, then I bottle. 4 weeks is probably overkill, but I have noticed a huge difference since I stopped using secondary fermentations.