I enjoy exploring the designs, patterns, textures, and motifs that are possible by making black marks on white paper. I usually spend a few minutes a day on most days engaged in this enjoyable (for me) activity. I have been doing this regularly since I graduated from high school. The other day I "did the math."
0.25 hours/day x 300 days a year x 50 years = 3,750 hours.
This is an illustration of the application of the "law of incremental engagement." It applies to other activities as well.
A page from Fred's sketchbook. © 2013 Fred Montague