1. You asked about products, but I find a critical factor is making sure the tires have adequate pressure. The Schwalbe tires are supposed to lose air slower than others (I think true, but you still need to check your tires carefully).
2. I used Mr, Tuffy liners for quite a few years. My results were mixed. When they're new they help, and are good for debris near the tread, not very useful if large staptes or screws penetrates the sidewall. After too long (7-8 years?) I found they dried out and cracked, so they actually caused flats. It might be necessary to change tire/tire liners more often.
3. Marathon tires - I used regular Marathon, not Marathon plus. Work well, but only used for a bout 8-10 months, vs. 25 years commuting/riding 50-100 miles per week.