I got a concert flea ukulele on ebay and have been having a great time with it. However, it totally doesn't hold tune. Weeks after putting on new strings, I'm still pulling it up every time I play. I had a Luna before this, and it held tune very well. Is this just the way the flea is? Would it be better if I got the optional peghead tuners? Or should I just get used to sweetening up the tuning whenever I pick it up?