MX518 for life, this mouse has been used daily for over 10 years and I have a spare one just in case I need to replace some pieces, which never happened so far.

I do no longer use it for gaming since its now outclassed but it is now being use in my office and may one day die in peace after such a long life span.

I wish they would upgrade the internals and keep the same design which is honestly reliable and comfortable, I have never owned a mouse which fits my hand like this one does.