I'm not pro. I just shoot photos for me. But, I want to decide what I'll delete and what I'll keep, not have that determined by a card/technical failure. I've accumulated lots of cards over the years. I use Sandisk, but that's only because they have always worked for me. +1 on buying from a reputable retailer.
At this point I shoot a 5diii and have a 64 gb SD in the second slot as a jpeg backup. If I ever really need faster fps or have buffer issues, I can always pull that card out. At this point I carry a collection of 8 and 16 gb CF cards with me. I get hundreds of RAW on each and rarely need to change out a card during a day. If I know I will be taking lots of photos tomorrow, I'll swap out a partially full CF card tonight with a fresh one. And, since I am a "belt and suspenders" kind of person, I back u to a portable HDD I carry with me and do not delete any CF cards until they are downloaded onto my pc and backed up. The size of the CF cards depends on what you think you realistically need for a day of shooting.
So, original RAW on a CF, backup jpeg on an SD, backup CF on a HDD, then keep all originals after loading onto my pc and backing up that drive. Hmm. Maybe I am a bit OCD about this.