To Model or Not to Model

When do we artists need a model? Moving along in a similar vein to my last post, I now ask the previous question. I think along the way most art students form a habit of using a model. After all when you go to college they make you draw from casts and setups and live models are brought in to shed their clothes for a few hours. Models, models everywhere.
I started my career without the benefit of college. I decided to get a sketchbook and start drawing. I drew what I saw and I drew what I imagined. My sketchbook became a diary of ideas for me. I sketch ideas in it pretty constantly. I don't always draw; sometimes I write out my thoughts and ideas. I'm very used to drawing anything. I don't need models for too much but it may add to accuracy if I had them. Paintings are done the same way for me. If I paint people, I like a model. There is a lot of information in a face and a model is helpful but more so just the set of the head and the position of shoulders is what I find most helpful. Put the head on wrong and everything is wrong. I can actually paint a very good face without a model. I think I've drawn enough exact portraits that I can piece something believable together. I digress here as I wanted to point out the flower paintings in this post. The one on top was made up. I did see some similar flowers in a photo. I noted the wrinkled type of pattern and the white boarder around the dark petal. I then just made up a painting. I preplanned the colors. They are different but similar to the flower I saw in the photo. I made up a background and hadn't even decided what to do until I was well underway. I had painted the star flower and washed in some green around it. I started painting a sky and for some reason settled on a distant tree line. I struggled hard getting everything to work. This can often happen with a painting.
The bottom painting was painted from a set up. I put the flowers in my blue vase and sat it on a table by a window. Now even though I had a setup I had to play with things. I didn't have flowers bending down as I wanted so I made them up. The background was dark but not as dark as I felt I needed it. I darkened it. The table didn't have the value contrast I wanted so I made it as I wanted. In both cases I ended up with a decent painting. One with a model and one without. The question remains: To model or not to model?