How do you mean? Do you want to back up a lot of info, or a normal amount?
Dual layer(make sure your DVD drive is dual layer with the DL designation) can store more info-costs more than a single layer, which, of course stores less. I find that Maxell CDs/DVDs the entire label/recording surface CRACKS AND PEELS right off the plastic disc counterpart if it is washed (yes, I wash CDs and DVDs
)-so if you are obsessive compulsive with washing, avoid these.