I store my stuff in a cool dry basement without major sunlight (glassblock windows all around).

Never had issues with mold or batteries exploding, nothing is sealed airtight (except some shrinkwrapped programs).

Vacuum packing anything with sealed liquid capacitors is asking for trouble.

No matter what you do stuff will still yellow and parts will still decay. All you can do is minimize major swings in moisture, temperature, sunlight, and chemicals and fix what breaks as needed.