That's 8 plugs and some super glue...doing a surprisingly pretty alright job of holding things together. It pains me to toss out a brand new tire, especially when I don't have another equal one to replace it.
Tires are undisputedly one of the most critical pieces of equipment on a bike. They're also one of the fastest wearing components, especially if you're smashing out bike park laps or live somewhere with lots of sharp rocks. Opinions on what the best tire for a given riding locale or season may be are a dime a dozen, and if you walk into three different bike shops in the same town you're likely to get three different opinions on what to choose.
The cost of tires has only increased over the last decade, and there's nothing more deflating than puncturing a brand new tire, but it happens. If the worst occurs, I usually find myself putting more effort than ever into plugging a punctured casing, and I'm much more willing to run a tube for a little while, especially if I don't have an appropriate spare tire kicking around the garage. We used to run tubes with a dozen patches, so why not tires with a dozen plugs?
If one is so fortunate to actually be able to wear down the tread on a tire before slicing the sidewall or otherwise blowing out a tire, there's certainly a point at which the performance degrades...the knobs peel, lose their sharpness, and with that, you lose your connection to the terrain and at some point, it's inevitably time to throw on some fresh treads.
How often do you replace your tires?