And, if your engine has been on a diet of "non-detergent" oil, you want to continue with non-detergent. At least until you have a chance to tear down the motor and physically remove everything that has settled in all the passages and horizontal surfaces.
Putting detergent oil into an engine run a long time on non-detergent causes the "settled out" stuff to lift (that is the point of a detergent oil) and travel "uniformly" throughout the engine. A "slug fest" of crud all appearing at once. And crud CAN get lodged in passages or orifices feeding say, the connecting rods?
Better to leave this crud as a "sleeping dog" until you have the chance to take it out and examine all passages and bearings in the process.
Many still prefer a non-detergent oil. All that crud is there, but doesn't hurt anything. The thought is that the crud is effectively "trapped" and the engine itself acts as its own "oil filter."
And many who do use detergent oil prefer the add-on filter accessory because in their mind the filter substitutes for the engine.
I tend to fall into the former thinking. And I have continued running my engine on a non-detergent oil EVEN AFTER A REBUILD and "starting fresh." But I can understand going detergent, especially if the engine is "pressurized" or has inserts or the filter mentioned.
Joe K