My mother was a very good comfort-food cook and always used Bisto and changed to granules later on. She usually grilled meat so there wasn't really much liquid to use for a gravy. For the Sunday roast she would use the juices but dripping toast was also a great favourite with us so she kept some back.
I don't often do gravy, now I come to think of it. Can't get Bisto here in Germany, of course. There are plenty of similar things available but usually in portioned sachets or little boxes, so you can't control the thickness or the quantity very much.
Instead of gravy I often use a white sauce, a red wine sauce or a lemon/butter sauce. I think I'll try out some of the methods described here, but only when we have visitors who eat meat.