I use Time Machine on my mac to back up things on a 2TB disk. I can go back to weekly backups as far back as about 6 months ago (it uses a trick that only adds stuff that has changed, so my 1TB disk goes a pretty long way on a 2TB backup). As a result, I don't have to worry about this. I don't know what's out there for windows folks, but there should be something similar. Carbonite's anual cost is cheaper than buying a large disk these days and should be very safe. If you go that route, you could rebuild even after a fire (once you got replacement hardware, of course).

As for download manager, I have no problem if that's on option, but I won't use it, and I won't make anywhere purchases if I'm forced to (I'm begrudigingly willing to tolerate the likes of Smith Micro since it's only once or twice a year that I'll use it). I tried using DAZ' downloader, and it made a huge mess and installed a bunch of old V2/M2 stuff that I'll never need. After wasting hours of trying to sort through it, I switched to downloading their zip files and manually install them just like I do with Renderosity stuff. If they stop offering zips, I will stop buying from them and the same applies to Rendo or anyone else that sells poser content.