Your dependency on backdrops depends on the camera format, film and ambient and accent lightingof a scene.

With 35mm shallow depth of field is not always available, even with slow films.

Meduim format and 100 speed film indoors usually means depth of field of a few inches is possible, even with some substantial flash energy.

Large format is shallower DOF yet again.

So figure out your gear and the apertures you will be working with. That will tell you the depth of field to expect. Then you can learn the influence that backgrounds will play.

The other issue is space. Almost any backdrop can work if it is big enough and you are far enough away from it.

Space is not always available to me, so I tend to carry a muslin backdrop and backdrop stand for on location portrait shoots.

I find muslin is easier to deal with than seamless paper out of my studio. Stuff the muslin randomly into a storage bag, and pile it on top if the modifer and stands bag and you are ready to travel.

To use it , stretch it over the support frame, and let the extra drape on the floor. As long as you dont edge light it, and can place the model five feet away from it, the wrinkles do not show with my meduim format rig.

Hope this gets you started on options that play into backdrop selection.