Spark Plug tubes/o-rings - If one plug is leaking, buy new for all?

[JoeFromPA]

Hi all,

In the middle of my 60k maintenance. Noticed some oil accumulation coming out of one spark plug area - the one on the passenger side most towards the front of the vehicle. Definitely coming out of the plug region and not anywhere else. Enough to stain the metal and have one drop hanging off the metal, but not enough for me to have ever seen any consumption.

Anyway, just thought I'd ask before I order....does anyone recommend replacing all the tubes/o-rings if one is leaking, or just one?

I am on a budget, but want to do it once and do it right.

Thanks!

Joe