Weight lifting gloves serve many purposes while lifting weights and performing various exercises. Among these purposes are hand preservation, increased grip, and added wrist support. It is a personal preference on whether to use them or not during an exercise routine. The best approach is to try exercising without gloves and acquiring them later on if one is displeased with the effects the workouts are having one one's hands.
Some exercises require that a great amount of pressure be placed on the hands to control the weight (lat pull-downs for example). This pressure can lead to discomfort as well as calluses, blisters, and chaffing. Weight lifting gloves help to alleviate some of the pressure by absorbing it into the fabric instead of it going directly into the hands. If one prefers the natural way of lifting (without gloves), constant lotion applied to the hands may be used as an alternative to weight lifting gloves to preserve the integrity of the hands. One should not apply lotion immediately before a workout, only after.
Weight lifting gloves offer an increased ability to grip the bar without it slipping. The leather used in the gloves is generally enough to keep it from slipping without the addition of rubber grip dots. The placement of these tiny rubber dots (especially along the based of the fingers) aid in keeping the weight from slipping. Another benefit weight lifting gloves offer is the reduction of sweat transferring from the palms getting onto the bar. This keeps the grip dry and allows for a firm hold without the barbell or dumbbells slipping.
As with many of the pressing motions (incline bench press with dumbbells for example) required to perform exercises, the wrists are under constant pressure. Some weight lifting gloves not only cover the hands, but the wrists as well. These gloves work by keeping the wrists straight which prevent damage to the ligaments, therefore preventing injury.