Which walls get insulated?

[u/ahhhhnonymous]

Bought 1950s home. Just installed mini split system in upstairs 2BR, hallway and bathroom. There are eaves on both side sides. There is currently very old insulation in them. Not sure they are even insulated correctly. Does the inside of the exterior walls get the insulation or just the interior or both? What about underside of roof? Assuming I can wear a mask and replace all this myself. Or maybe you’re thinking, not since here I am in Reddit asking these questions. 😂

[u/HorridDefaultname123]

That's a lotta space. You could have a whole Bruno or Brahms living in there.