I've been collecting set and legendary Blacksmith plans as I level my characters, and I teach each of them to Haedrig as I find them. Recently, though, I've started to notice that only a few of these plans are used to make level 70 items, so I'm hesitant to keep collecting them unless I'm playing on a maxed character.
What I want to know is whether or not the level of my character at the time I obtain the plans will affect the level of the item(s) crafted from those plans. (If there are any differences in this regard between legendary and set plans, details would be appreciated.)
If character level does have some effect on what level the crafted item will be, is it possible to get another version of the plan later for a higher-level version of the same item, or am I stuck with the low-level version?