Baseball gloves were not originally part of the uniform when baseball was first played in the 1870's. Back in those days, only the youth used these mitts, because adult fielders who used gloves were considered 'weaker' in that they could not take the force of catching the baseball by their bare hands.
Taking inspiration from early hand armors like mittens and gauntlet, the first baseball gloves were hardly ergonomic - they were just pieces of leather padding that covered the palm of the hand, with holes for fingers to fit through. It was only twenty years later that baseball gloves officially became part of the baseball uniform. The gloves became bigger and gave better protection, similar to the baseball gloves we have today.
Baseball gloves became such necessities that in the 1900's, manufacturers began producing different gloves for different player positions. Smaller gloves were made especially for pitchers and infield players, and significantly bigger versions were made for outfielders. First basemen also began using unique mitts. It was also around this time that hybrid 'utility gloves' became popular to fielders who play multiple positions.
Modern baseball gloves also became more functional: they now provide protection and support not only for the palm, but for the metacarpal area (back of the hand). Their designs have even been changed to better conform to natural grooves of a player's hand. 'Fitting' became more scientific, and buyers began to follow sizing guidelines when purchasing gloves. The measurement is quite simple: the size of the glove is equal to the length from the 'heel' of the glove (resting on the wearer's wrist) to the top of the glove's palm. Youth gloves usually measure 8 inches to 11 inches, while adult gloves measure about 12 to 13 inches. Official baseball games require players not wear gloves longer than 12 inches.
Prices of gloves have also become quite competitive recently, concurrent to the boom in baseball glove manufacturing and in the interest of people in baseball itself. As a rule, beginners and children (who will likely outgrow their gloves fast) do not spend too much on their first baseball gloves, and tend to stick to the $15 to $25 range. Those more serious about the sport, though, are willing to spend as much as $150 to more than $200.
Expensive baseball gloves are considered by some as investments; well-made ones with good leather and stitching can even be passed on from generation to generation. But with proper care, even mid-priced baseball gloves can last through lifetimes.
Cleaning is one sensitive issue. The wrong kind of glove cleaner can make the dry out the leather, causing cracks and deformities on the baseball glove. That is why experts stick to the good old petroleum jelly, which, unlike linseed oil and silicon sprays, keeps the pores of the leather open and lets the glove breathe.
Storage is another issue. Since heat is the number one cause of the baseball glove's leather deterioration, baseball gloves should therefore never be left in places where heat can deteriorate its leather, like in car trunks. If the glove gets wet, it is best to dry it with a towel and hang it out to completely dry. The glove's laces should also be kept tight, so that the glove does not lose its form.