Comment 2 for bug 91447

I don't; that's what this bug is about, upgrading laptop-detect should pull in the correct version of dmidecode.

But if you're asking why I would issue a command like 'apt-get install laptop-detect', there are a couple of possible reasons:
1) In this particular case, IIRC, I wanted to keep the mythtv version of dapper (performance issues on that hardware with the latest version of mythtv), but upgrade the rest of my system. So I did a piece-wise upgrade (and laptop-detect was among a bunch of packages after 'apt-get install').
2) Free disk space constraints. Sometimes you do not have enough disk space to do an apt-get (dist-)upgrade, and have to do it in pieces (running apt-get clean in between).