One of the best things about the Oral-B toothbrush, besides the fact that it gets you 
mouth squeaky clean, is that they have been nice and kept many parts interchangable. This means the update brush heads they just released work on my older toothbrush.
Oral-B also sells all of the parts for their system seperatly. You can buy a second charger or a newer power handle. I was able to buy a new Oral-B Sonic Complete handle and it the charger from my older Oral-B 3D.
So what does this all mean?
- If you are already an Oral-B owner, it is really cheap to upgrade to a newer system. Since almost all of the handles use the same charger and brush heads you can simply buy a new handle. Instead of having to an entirly new setup you can simply upgrade the parts you need.
- You can switch to a Sonic Complete style handel and still use the same charger. It is much cheaper to buy a sonic handle and bursh headsd (~$65) as opposed to $120 or so.
- Another great thing is that they are always coming up with new brush heads that work with the older burshes. This is great, it allows you to use some of the latest technology without having to do any dramatic upgrades.
Oral-B fully supports this. You can buy all of their parts directly from them here: