I'm on my 3rd pair of Salomon Quest 4D GTX. Generally, the rest of the boot is failing by the time the sole is worn down. However, I find the GTX membrane doesn't last very long, particularly if used in fine dust conditions as this seems to work it's way through the boot and chews up the membrane.
Overall they are a great boot, they typically last me about three years of moderate use. I figure I hike about 100 km a year or so.
The reason I've bought three pairs is they fit me excellent and they are better than my heavy and stiff Scarpa boots when the load carrying ability isn't needed. I also find the flexibility nice for finding traction. The light weight is very nice too. And more support than an ankle height trail shoe.
Specific to the Salomon Speedcross shoes, don't use them on any non-loose surface as this just eats the soles. They are made for dirt, mud and the like. Rocks, pavement or in your case, tile are too grippy and tear or abrade the lugs off the soles.
