Quoted from RyanStl:I sold my old DW to a friend years ago. I only see him about once a year and every time I ask if he has replaced the batteries. The anser was always no. Not long ago he had a 40th b-day party and I bought him new lithium AA's and replaced them for him, 7 yrs later. I then had to get all my high scores back.
You can leave the power ON when replacing the memory batteries in WMS games. This way you won't lose the high scores etc.