Altho a lot of people shun against it, I got my little man Caliber at 6 weeks. And even tho he was, in 99.9% of peoples eyes, taken home "too early" he did just fine with everything. He was already weened, his health checked out fine, he was running around playing, he crate trained fine, and was housebroken within a month and a half...I think the only time I've ever seen him 'sad' was the drive home...but he fixed that by hoping over the center console, and snuggling into my lap 
The rest after that point is history...he's been by main man, and shadow since. Now, I'm not saying that it's right to take home a puppy at such an early age, but I think I got lucky with Caliber...we had such a strong connection from the get-go, and I visited him a few times in the last three weeks before I did take him home. If I had to do it over again, I'd do it the same way, however, because I'm sure I got lucky, my next pup will wait until he/she is 8 weeks or older before I take them home. No way can I be lucky enough for it to work out the way it did a second time around! But ideally, a pup should be taken home no younger then 8 weeks. And I'm sure a few of our Sheltie Rescuers will say that it's never too late to adopt an older Sheltie. I think as long as you have an idea of how difficult is may or may not be, you can never adopt a Sheltie that is "Too Old" 
After-all...they need a loving home just as much of the rest of them do!
The rest after that point is history...he's been by main man, and shadow since. Now, I'm not saying that it's right to take home a puppy at such an early age, but I think I got lucky with Caliber...we had such a strong connection from the get-go, and I visited him a few times in the last three weeks before I did take him home. If I had to do it over again, I'd do it the same way, however, because I'm sure I got lucky, my next pup will wait until he/she is 8 weeks or older before I take them home. No way can I be lucky enough for it to work out the way it did a second time around! But ideally, a pup should be taken home no younger then 8 weeks. And I'm sure a few of our Sheltie Rescuers will say that it's never too late to adopt an older Sheltie. I think as long as you have an idea of how difficult is may or may not be, you can never adopt a Sheltie that is "Too Old" After-all...they need a loving home just as much of the rest of them do!