Multi-years, not a couple or less
If the Denver Broncos are going to be successful as a unit, there is absolutely no reason to bring in a guy who will only be around for at least one season. It could really throw off the chemistry among the players, especially on offense.
Plus, what were to happen if Tom Brady got injured and missed a handful of games? After that season, the long time quarterback could decide to hang them up and listen to his body. Which will be covered more in a bit.
While the idea of winning another Super Bowl as soon as possible is great, does it really make sense to have a quarterback around for only a year or two?