While the importance of playtest might seem obvious, the practice took time to catch on and gain acceptance. In the late ’90s, it was still pretty routine to run into developers who didn’t playtest the games they were working on.
Luckily, I earned my bones at Ensemble, where there was never anything else. As the only founder with much real experience making games, Bruce Shelley was often responsible for providing us with some clue as to what we should be doing. Playtesting was the process he had seen work in the past. (Apparently, the development loop for Civilization involved Sid Meier writing some code, then Bruce playing and making notes, then Sid writing some code, then….) Ensemble started with it and we never questioned it.