My mom's old machine (that I broke making a tent?) had this diagram with maybe 20 locations where you're supposed to apply a drop of oil. And it was tricky to set the tension and keep it from losing stitches. And it collected lint that had to be cleaned off.
I have a Janome that I have never oiled. I've vacuumed it out inside a little, but not very much. I never adjust the tension. Occasionally, like when I sew Velcro, there is a "rat's nest of thread" on the back side, but if I just let go of the fabric and let it sew it works okay. I've made maybe 8 tarps, 5 packs, 4 jackets, 8 pants or shorts, 1 shirt,... so I've used it quite a bit.
I think newer machines are better.