Flats are pure luck, or lack of it lol You can get 10 flats in a week, or none for a year. Most stuff that causes flats/slow leaks is hardly visible when embedded in the tire. Most likely tiny, very tiny piece of rusted wire, or incredibly small piece of glass. Don't expect to see it right away. If you find one - double, triple check for more.
Any tire and tube can be punctured easily. You also should check the rim/tape itself for sharp edges. I buy tubes from Performance Bike. They are pretty cheap, and very good quality made.