How about the last one?

For the silent deflates, 4 in 4 months isn't that bad. Inspect the tires carefully running your finger along the tire with it turned inside out. Tiny bits of wire or chips of glass/rock can work their way through and this is totally normal. These guys that say they go forever without flats are riding clean roads. I've ridden bad roads and good roads. On good roads, I can go a year without flats. On bad roads, I get loads of flats with *any* tire, including the Marathon Plus which people hype as flat proof. That blue layer does provide a huge amount of protection, particularly against glass chips, but sufficiently bad roads will wreck any tire.

As a matter of fact, you should inspect your tires for tiny embedded chips regularly and pop them out with a blade. Otherwise, they'll work their way through and puncture the tubes.