I use a ramp for the van, but not in the house. I have dog beds scattered all around the house so the dogs have a choice of curling up in one of those or climbing onto the couch. We did build a ramp onto the porch for the dogs (we were also replacing the porch steps).
We also have a three-legged cat who is getting older and having a harder time getting up on his favorite bed (my sister's). Sis built this ramp for him, complete with handicat railing.