Back in 1985 I purchased a Tasco 3-9x40 World Class Scope. I put that on a Ruger M77 in 7mm mag. And at the time, that was a fairly expensive (for the little I was earning then) scope for me. That scope has been on that same rifle for 27 years and I have NEVER had to adjust it. It has never failed me. It has never caused me one bit of grief. And it really is a good scope. Back then Tasco was a very reputable scope company that sold high quality scopes. And they still do I am sure. But I was so impressed with that scope, I saved money and put one of my Remington Woodsmaster 742 Carbine 30-06. Again, I have never had to touch that scope.
Since then I have purchased Leupold, Redfield, Bushnell, Nikon, Simmons, and all of them are great scopes. But it is hard to believe how well those old Tasco scopes have held up.