Everything makes a difference. Unfortunately, the masters of the craft are long gone, and those of us who are left with tubes and their sockets don't even know what we don't know.
Example - to work reliably, the socket connector material must be have enough of a linear bending range to accommodate repeated tube swapping without losing its grip. Sixty years ago socket makers understood what alloys and annealings would serve this function best and/or most cost-effectively. Their sockets frequently used Bakelite, so now we think that Bakelite is a good socket material. Today, we have tubes with metric approximations of the standard dimensions - so the demands on the metallurgy are more extreme - but the third-world socket factories do not have access to the metallurgical knowledge and often don't even use the traditional materials. And we users are too ignorant to realize this. There are no big (RCA etc.) factories using billions of sockets with research departments checking up on the factories.
So now we have teflon, which handles heat very well and has an admirable dielectric constant. That's important in capacitors but much, much less so in a tube socket. We are entering the second generation of teflon sockets and a few manufacturers are addressing the problems that appeared in the first generation; naturally it will be ten years before we know whether these changes will extend the socket's life to ten years.
Just sayin' ...
