What is there to say about motor oil...its a liquid that spends most of it time in an oil pan.
If you have been around cars for a few years, perhaps there are a few things to say...
Let's engage a conversation.
Back in the day
If you remember from way back in the day when motor oil was a straight grade 10 or 20 or 30 and in cold winter climates 30 was a summer oil. Then there was the advent of multi grade 10 W 30, or 20 W 40 and so on.
Oil changes were supposed to be performed on a regular basis since oil would deteriorate rather quickly.
All the urban legends in one fashion or another regarding oil, and the qualities of different brands, and so on. While everyone had their favorite brand of oil.
Doing your own oil change was fashionable.
Way back in the day an engine oil filter was not standard. Agreed...there was alway additional "stuff" in engines. When filters started appearing they were paper and were installed in a removable metal container. Back then filters were quite large and easily contained at least 1 liter of oil.
The advent of "spin on" filters made it much simpler to replace a filter, although at times removing a spin on was a challenge.
If you had performance inclinations back in the day, and perhaps had a blueprinted engine, or partially blueprinted engine. The clearances were slightly more generous to diminish friction in the engine, and you would use a heavier than lighter grade of oil.
Most oil pans were 4-5 liters, and the filter was close to 1 liter...was it enough oil? Needless to say that you also wanted to keep the oil away from the crankshaft. Ideally if you had intentions of having a strong running engine you also wanted to cool the oil.
Back to oil...yes you would use "straight 30" and wait to warm it up before getting close to the redline. When multi grade oils became available you would use "20W40".
If you did not wait to warm up the oil...you quickly learned that it could come out of the engine by all the breathers and literally make an oily mess.
Today we have a vast choice of synthetic oils from a myriad of sources. Similar to the old days some brands are even recommended by manufacturers.
Oil change intervals are appreciably longer than the 5,000 kilometers from back in the day.