Don’t chance to luck, buy a second memory card for your camera.
Every time you have a shoot that is unrepeatable (a holiday, relatives coming to visit, etc) shoot half of your images on one memory card and the other half on the second memory card.
This way, if one memory card goes faulty or you accidentally delete a card, you will have a backup and still have images from the shoot.
On unrepeatable shoots, I will use two cameras, and split the shots between the two, but if I only had one camera, I would use two memory cards.
If anybody has any questions about any area of photography, Pete will be pleased to answer them for you.
Just email firstname.lastname@example.org.