From what I've read and heard coaches (and retired coaches) say; most teams have only one or two practices per week in pads during the season and they are generally somewhat short and mainly to work on fundamentals. If the coach thinks the team is getting sloppy with the fundamentals they will have more work in pads.
The rest of the practices are either just in shells or shells and shoulder-pads with no hard hitting. These practices are more for learning or practicing plays and running through the gameplan for the upcoming game.
Denver rarely practices in Pads (Shanahan), and the Commanders often practice in pads (Gibbs). With "Run and Gun" Super Steve, the Commanders rarely practiced in pads.