Newer golfers and high handicappers are often afraid to take divots. This is due largely in part to the negative association with divots they've taken in the past. Most of these chunks of turf that they've dug out of the ground have started before the ball, resulting in fat, ugly shots. Divots are good (and essential for proper contact), providing they occur after the ball is struck. Ideally, the clubface should contact the ball, then bottom out on its swing arc after contact and under the turf (thereby taking a divot). This is true for all clubs except the putter, driver, fairway woods off the tee, and when hitting short chip shots.
The negative association with taking divots leads the golfer to try and 'pick the ball clean' off the turf. This discourages the descending blow that is required to get the ball on the correct trajectory, and encourages a weak, wrist-y shot in which the golfer 'lifts up' at the ball rather than hitting down. Many 'topped' or 'thin' shots will result when using this method. Hitting down on the ball is the only way to achieve good distance and get the ball up in the air.
A divot should be taken with every iron, because every iron should be hit with a descending blow (a fairway wood should also be hit with a descending blow, but so minimally that a divot likely will not occur). The more loft on a club, the bigger a divot should be taken. This is because the more lofted the club, the steeper the swing plane (and more of a descending blow). As loft decreases, the swing plane flattens out and the strike on the ball becomes more of a 'sweeping' blow (although still hit on the downswing).
One of the reasons I encourage practicing in the grass whenever possible (as opposed to off a driving range mat) is because this is the only way to get a true indication of how you are hitting the ball. A mat can be deceiving in that you can still hit a ball fat (contacting the ground before the ball) and get away with it to some degree because the club will sort of 'drag' along the surface before contacting the ball. When a fat shot is hit on the grass an 'incorrect' divot results (divot is taken too soon, the turf slows down the clubhead speed, and the clubface either does not contact the ball at all or it contacts the turf before the ball).
When addressing the ball, I believe the golfer should set their hands slightly ahead of the ball and clubhead for all clubs except the driver and putter. Again, more so with the more lofted clubs and less as loft decreases. This will assist in hitting down on the ball and taking an appropriate divot, because when you mimic your intended contact position at address you have a better chance of returning to the same position upon contact.
In addition to the other benefits, a divot will give you instant feedback about your swing. If your divot is very shallow (or non-existent) for a lofted club then you didn't hit the ball on enough of a steep, descending blow. If your divot is huge for a fairway wood then you didn't hit the ball on a flat enough swing plane. Is your divot pointing to the left? Your swing path was outside in and the club released to the left of your target line. Is your divot pointing to the right? Your swing path was inside out and the club released to the right of your target line. Is your divot pointing along your intended target line and the appropriate size for the club in your hand? Nice work.
Take a divot to play better golf, but please remember to replace it!
