AK-47 recoil springs guides

[walking arsenal]

I was reading about different AK models and i noticed that some have the tube style recoil spring guides and some have the loop style. My romanian has the loop style and im curious if i should kick in the 35$ and order one of the tube style.

any thoughts?

and does anyone know IF there is a number of rounds you should replace springs at or is it a if it works dont fix it kind of thing.