On my 96 dakota and my 97 wrangler I pulled the cat when they started rattling and put in a pipe while I was going to order replacements. I never got a CEL so no new cat went in. I still have the dakota. O2s still in factory locations, and 50k miles (and counting 70 miles a day at a time) still no CEL.
Fast forward to my 01 Durango with a 360. I have had for going on 8 years. That damn thing, had a inefficient catalyst code that drove me nuts that I was able to stave off for a while with an old spark plug non fouler between the sensor and the bung but shortly before the original engine had to be replaced (at 258k) I had to replace the damn thing. I'd replaced O2s a couple of times prior to that.
I had had an injector stick wide open on the replacement engine which killed it in short order. And melted down that brand new cat. Replacement engine number 1 (a complete and total rebuild included all necessary machine work) lasted all of 3 hours and less than 6 miles, and it killed that new cat. While I waited for my son and tow strap I watched the cat glow BRIGHT cherry red.
So when I got around to putting engine#2 in (a CL buy with about half of the miles that the durango has on the body, all regasketed with the brand new EQ heads that Id had on replacement engine#1) I put a pipe in in place of the cat with (again) a new round of O2s. That SOB went all of 162 miles before the CEL came on due to inefficient catalyst. So I had no choice but to buy another one. Was none too happy about that. So far 15k miles since engine#2 and cat #2 went in and so far so good...
I treat cat converters like an uninvited house guest.as long as they cause no issue I leave them alone. As soon as I have a problem out they go.