Only if a board needs it.
Before using a board I lay it on a flat surface and alternative tap on opposing corners. If it rocks it gets joined. If it doesn't I altenately press on the center of the ends of the board. If it rocks it gets joined. If it passes those test it gets turned over and the process is repeated. Any rocklng and the board's face gets joined.
If the faces are flat I check the long edges for straight. Again, on a flat surface, the board is set on edge and the ends pressed on looking for any rocking. If there's any rocking the edge gets joined.
Finally I'll check that both long edges are square to the face using a small machinist square. If they're not square the board gets joined and the opposing edge ripped.
Found out early on that you can't make rectangles out of trapezoids and the importance of flat, square and straight.
charlie b