Oils
The best you can afford is usually the right one.
If you have a budget for cheap only then change it more often thats been my motto.
With increased prosperity I have gone fully synthetic but I still change it every year regardless of mileage. I even do annual partial oil change of my ATF as its got a magnetic plug so I can worry about the metallic swarf build up.
Next engine oil change I will fit my recently aquired magnetic sump plug (Opie Oils one) to give myself more to fret about.
Its the insecurity of owning an older vehicle that keeps me going in my creeping old age.Lol