Although non-direct, I base NPC reaction on total level. People may never have heard of you until you are 5th level and then maybe only in the local area. 10th level you name starts to be known by many in the region and everyone in power. By 15th level most everyone has heard of you and can recite a few of your deeds, and may greatly add to them.
At low levels you may get a few free beers and a night sleep at the inn. At higher levels you gain other favors like a visit with the duke or a keep of your own.