There are two simple ideas to keep your gloves fresh...
#1. Two different pairs of gloves. Make sure you use a less expensive pair of gloves or an old game pair during training.
#2. Proper glove maintenance. After every couple of games (especially muddy games), wash your gloves. There are two methods. First, simply drop your gloves in the washing machine with regular clothes on the regular cycle with regular detergent. DO NOT put them in the dryer. Let them air dry.
Second, you can hand wash your gloves. Simply put your gloves on and use a mild dish detergent while washing them under warm water in the sink. Wash thouroughly.
Be aware-- there is usually an overnight drying time for either method. DO NOT rush drying or you will ruin your gloves. Finally, with gloves, you usually get what you pay for. Cheap gloves will last a long time but do not have the gripping ability of more expensive gloves. A good pair of gloves will last a season or maybe a season and a half. After that, they should be shifted into the training pair.