I replaced the plugs in my '06 Matrix at the 10 year mark and ~60,000 miles because I was concerned they might be difficult to remove.
They were reluctant and needed some back and fourth finesse.
There was no change in performance and the electrodes looked almost like new (irridium tipped).
They could have gone much further, but it’s a fairly easy DIY job, not expensive; and I felt pretty good afterward.