Fresh install for 10.6 upgrade?

Late last year, I attempted to install Snow Leopard on my Leopard machine (10.5.8 at the time I believe) and right away, I began to notice the OS doing strange things during normal use. I opted to use Time Machine to restore it back to Leopard, but it wasn't the same and eventually had to reformat.

I'd like to give it another go, but is it just standard procedure to start with a fresh install of Leopard when doing this? As my primary work computer, I can't really afford to have it go belly up again, but would like to have some of the benefits 10.6 offers.

I'm assuming when you installed Snow Leopard the first time, you installed it over the top of Leopard as an upgrade? Sometimes that will work OK, sometimes not. When I first installed SL over Leopard on my 2008 MacBook I could not get past the kernel panics. Yet, when I installed SL clean and used a TM backup, all went well.

You didn't mention anything at all about which Mac you have, but a clean install is always better than an upgrade. However, if your machine has been around for awhile, you might want to test the hardware first either by running the Apple Hardware Test, or a Disk Utility verify and repair when booted from your Leopard DVD.

It's an '08 MBP, and yes, I was installing the upgrade on top of Leopard. Installed fine, just had some odd quirks.

As suggested safer and better to do a clean install after backing up system to an external drive.