Re: Some say 6 mos., petsmart clerk said 1 yr?
I switched Kodee to adult food around 5-1/2 mos or so. I've heard both sides of the "puppy food til 1 yr" argument. Personally, I felt that it made more sense to switch to adult food earlier w/a large breed pup, as it keeps them from continuing to grow so fast, which is not good for their joints. This is the argument I decided made most sense to me - but like I said, other people go the other way.
I also agree w/Roxy - what I used to think was "the best" was Lg Breed Science Diet. Luckily, I found out when Kodee was still really small, that that food is one of "the worst!" So, if you're buying from Petsmart, you could do better, more than likely. JMHO.
As far as spay/neuter - I used to work for a vet, and I believed for years that spay/neuter by 6 mos was gospel. This is what I planned for Kodee when I got him initially. Luckily, I did tons of research after I got him (before I had him neutered, thankfully), and I have decided to wait until he is 2-1/2 to 3 yrs old, if I neuter him at all. He's a housedog, and never outside unattended, so we won't be adding to the puppy population, and I want him to have his hormones until he is completely mature/physically developed. Males tend to keep that "feminine look" permanently when their hormones are taken away before maturity. I may not neuter him at all - testicular cancer is not that common, and I don't know that I want to permanently alter him - I see no real reason for it in our case, unless I start seeing some behavioral issues, but even then, I will try to figure out some other way of dealing with them than surgery...Also JMO. I just suggest you do lots of research (look around for other opinions than just vets - they make their money on vaccinations & neuters, remember). Then decide what arguments for//against make most sense to you. Good luck!