Enamel smell usually fades as it dries and cures over a couple days. It should only be really proper fumey for the first few hours while the solvent is still evaporating though. After that it should only smell if you're within workbench distance or so. After a few days, it should only smell if you sniff it, or not at all. Enamels are technically a kind of oil paint so they do cure rather slowly.
If your room(s) are still fumey this much later, either the enamel isn't curing properly (could be bad paint, or undermixed in the bottle/can, or the material being painted has chemicals in it that are interfering with the paint chemistry), or the area isn't well ventilated enough for the "old" fumes to circulate out.
You say you painted a roof, how much surface area are we talking? Brush or spray? How thick of a coat? What material is the roof made of?
If you want to speed things up, you can try putting the model/part somewhere hot like an attic for a day or two. This depend on the climate where you live through: where I live, attics get pretty hot during the day, but If you're someplace cold this won't work of course.
Enamels are more durable than acrylics in theory, but in practice that gap has been closing over the years, and these days which is more durable varies by brand or product line. IMO as long as your primer is good, you usually don't have to bother with enamels these days unless you're doing something that deliberately exploits the long cure time in some way.