guitar strings does it matter?

I have used many different brand of guitar strings through the years. I have not been ablt to tell much difference in the feel or sound of them. Of course new strings sound different than old strings. But i can not tell a difference in brand. I have however thought from time to time that different brands lasted longer without breaking . I have used fender strings, slinky,blue steel , and i am currently using XL's . I have stayed with XL's for some time now becouse they are not easily broken. Maybe this is just a coincidence and a testiment to my playing being less aggressive as in my younger days ,who knows. But anyway i have found them to  a good string and hey if its not broke don't fix it. So that is what i plan to continue to use.