As long as possible. Why it's important to get something classic, not trendy.
No such thing, except for certain antiques and even so "brown" furniture is out.
For me, until I'm sick of it.
We are using a dresser that is over 60 years old (was bought by my in laws when they first married and they are in their mid 90's now). Yes, it was a light color, but we sanded and refinished it to a darker color, put on new hardware and it looks great. It is solid maple, very heavy, well built. It will last at least 3 lifetimes. It's in our son's room (he's away at college now).
We bought custom made furniture for our own bedroom years ago. Solid cherry. Easy to live with style. I'm sure our son will be deciding whether he wants to keep it or not. It shows no signs of wear. Hardwood Artisan (when we bought it the place was small and called The Loft Bed Store).
Don't buy at Marlowe. Buy quality and keep forever. At least on pieces you need to function well.