You can make dimension settings 'stick' by saving them as a named style.
When you do 'file', 'new', it normally allows you to choose the template drawing to be used. I believe the default is ACADISO.DWT
So any new drawing you make will inherit the text, dimension, line, etc. styles saved in its template file.
I find it easier just to take a known good drawing, 'save as' a different name, delete all the entities and start with a blank canvas.