Your book that came with your machine should tell you where and how often to oil your machine...I have a computerized Kenmore and I oil it 2 or 3 times a week depending on how often I run it because that is what it said in the book....the more it is used ..the more it should be oiled...but there is only 2 oiling spots... my much older Kenmores (two of them) require many spots to be oiled and the book says not that often...my service man also told me not to oil them very often.... but then if they DON'T get used for quite awhile to oil them before using them.....
SO...every machine is different.....but you need to read the book and find out what your machine requirements for oiling are....
I have to admit my mouth dropped open when you said you had NEVER oiled a machine and you've been sewing for 4 years! LOL Shocked me!