If the recorder is a few years old, make sure you update the Firmware on it; This will allow it to better accept the different types of DVDs. It does matter which burner your using, older types are more limited. So, newer is better.
I used to get a lot of burn failures until I found out about quality of your burner, Firmware updates, quality of your DVD blanks. Of course, the copy program makes a difference, too. As mentioned earlier, I use DVDFAB because it's user friendly, and updated frequently. A little expensive, but I purchased the separate modules over the years and always waited for 50% off sales.
Verbatim DVD brand has the least failure rates, AKA "Coasters" There are a couple of other high quality DVD brands, but are too expensive due to the types of dye and material used. I'm not recording for NASA, so I don't need mine to last 100 years. My Verbatim DVD movies have aged over a decade now. Some of the Blu-ray DVDs are about 5 years old. All still working fine.
Despite what burn speeds are advertised, I always go about 2/3s speed. You'll get better results.
Don't keep burning DVD after DVD without breaks for your burner. It will heat up and burn up before its time.
The Verbatim blanks can be purchased on spindles of 100, you'll get the best price that way...watch for sales. Plus, or Minus format doesn't matter much anymore. The new burners accept any format now. The Minus format is usually a little cheaper. But, I use the Plus format.
John