Im looking to buy a racquet, my racquets are 5/8 grip size, found a good deal for a 1/2 grip, i have demod 1/2 sizes, but never purchased a smaller size, is this goin to be a problem ?
I wouldn't think so, especially if you tend to use an over grip which would increase the size of the grip. I did this when I was younger and played in high school and was gifted a racquet with too small of a grip. I've also done this for my son's racquet, built it up as he's grown up.
My advice is if you find a good deal with a smaller grip, it is much better than finding a deal with a larger grip than you are used to...the grip can easily be modified to feel like a 5/8...I say go for it, and if you need help figuring out how to make your grip feel like 5/8, just return to the message boards and there's tons of people who would help. It is really easy to customize your grip to your liking.
I transitioned this year from a 5/8" grip to a 1/2" grip. This also coincided with a decision last year to reinvent my forehand into a more modern forehand. The smaller grip size actually lets me whip the racquet through quicker and is easier for me to maintain a loose grip. With the larger grip I had a tendency to hold the grip a little to firm in pressure moments.