R/W discs are made to be re-used. There is no outright command to keep them permanent. While your session can be finalized, the disc can be recovered and used again. Though, there is possibility some space maybe lost.

As for Memorex discs, I find them iffy at times compared to other name brands. I tend to buy Philips and TDK in DVD+R or -R. Alot depends on the manufacturing lots coming out and Memorex makes more than a few but seems to continue use of dies that others tend to pitch, so the choice it yours. My info is dated but continues to be proven, time and time again. I say that often enough, users with problems discs are Memorex brand. As a name brand, its the bargain brand but they're better than no named or generic bulk brands, IMHO.

tada -----Willy Happy