The 70/70 rule is folklore. Modern cigar storage is simpler, cheaper, and safer than what most cigar books recommend. Here is the actual system.
The setup that beats most $300 humidors
For collections under 100 cigars, the modern best practice is: Boveda 65% packs in any sealed container. A Tupperware with one Boveda 320g pack maintains perfect humidity for 50-100 cigars for 6+ months at total cost of $30.
This beats a $300 desktop humidor with analog hygrometer and propylene glycol pad. The desktop humidor will stop holding humidity within 2 years as the seal fails. Boveda just works.
Why 65% RH instead of 70%
The 70/70 standard (70°F, 70% RH) was set decades ago for tropical climates. At 70% RH with temperatures above 73°F, you risk tobacco beetle hatches. Beetles destroy cigars and infest your collection.
65% RH is the modern safe target. Cigars smoke better at 65% (less wet, better burn), store safer (no beetles), and are more forgiving in transport.
The system that scales
Under 50 cigars: Boveda 65% pack in a Tupperware or sealed plastic case. ~$30.
50 to 200 cigars: Spanish cedar lined wooden humidor or coolerdor (igloo cooler with Boveda packs). $80-$300.
200 to 1000 cigars: Wineador (modified wine fridge) or large cabinet humidor. $400-$1500.
1000+ cigars: Walk-in humidor closet or dedicated room with hygrostat. Custom build.
What to never do
Never use a Cuban-style mahogany humidor without lining it with Spanish cedar (mahogany absorbs nothing). Never use distilled water with a propylene glycol pad (use Boveda). Never store cigars in their original cellophane long-term (cellophane breathes but slowly, can trap moisture). Never store cigars in your refrigerator or freezer (kills aging, draws moisture).