so I have a 90 crx si that is practically stock with about 175, 000kms.

THe engine before I rebuilt it burned a tonne of oil and after I reringed the pistons it only burns a minute amount ever few 1000kms.

My car does not have the factory cat converter on it right now although i did find one in great shape at the wreckers and plan to install the used one sometime later on this week.

My car when idling smells rich and the exhaust fumes sorta make my eyes burn. I'm assuming that b/c its obd-0 that this is probably to some degree normal esp without a cat. My car generates decent power, doesn't throw any CEL (its a canadian rex if it makes a difference) and my air fuel ratio meter says its running stoich (how accurate this really is I'm not sure, its an autometer gauge).

I can get a new NGk o2 sensor for cheap that is a direct plug in replacment but I want to know when I should replace the sensor. I've been told by honda that they rarely fail and often will last the life of the car.

Can anyone here tell me if I should change it?

I've always run premium and my car has always been in excellent running condition.