This is still a bit fuzzy to me. Surely you're not saying that all four of these have been replaced 3 times in 2 years! (total of 12 parts)
If you are then I can only think of the following:
You're putting a 100k miles a year on your car.
You're living pretty much out in the boondocks and driving in a lot of mud and muck.
You're being gouged for unnecessary work and the parts are not being replaced or good parts are being replaced with new parts.
Symptoms of worn tie rods and tie rod ends include tire wear (often featheredging it's called), wandering on the road, etc. In extreme cases, the front end may clunk slightly.
All of the above would only be releveant if ALL 4 items were replaced repeatedly.
If this is a matter of tie rod end one month, tie rod 4 months later, another tie rod end 5 months after that, etc. then I could understand some of this.