Updating drivers in linux

[the dsc]

The actual situation is that I bought a bamboo tablet, which is not working properly yet. I think it's a driver issue, and the new one apparently is more suited to it than the one that's available on Lenny's repositories...

So, in general, how the driver management works in linux? Can we just install a new driver over an old one as if there were no driver at all, or should we uninstall a driver of something before updating to a new one? (as I've heard that it's the preferable thing to do with software, unless there's the "update" option in some package-manager like synaptic or adept).

And a hypothetical question. If someone were foolish enough to do the first thing before even asking for people who know more whether that would be the proper way to do it, would then this hypothetical silly person be in a very messy and troublesome situation, or the uninstall process would usually be the same, and enough to get ready to the driver update?

[Segfault]

Generally, in Linux we have two types of drivers.
0. Vast majority of hardware is supported by Linux kernel. The driver can be built into kernel or as a loadable kernel module, note - even loadable modules are still part of kernel code.
1. Userspace drivers. Built from source (open-source drivers, e.g. madwifi) or binary blobs (proprietary drivers, e.g. ATI driver).
In first case you get updated drivers when you upgrade your kernel, in second case you normally get upgraded drivers via package manager. Unless you use GIT, CVS, SVN version, then you do it manually.
To get help with your issue better be more specific.