How do you prevent scale on house plants?

I could be flippant, but seriously, you can't prevent them completely. It's
like, how do you prevent the common cold? Let's say rather, how do you minimize
the likelihood of scale infestation?
1. Buy only from clean, reputable nurseries.
2. Avoid susceptible species, like ferns, citrus, & Ficus.
3. Quarantine new plants for a couple of weeks, & examine them closely.
4. If you keep your plants in an enclosed room, use No-Pest Strips. They will
not eliminate established scale, but they tend to preven them from spreading.
5. If you find a plant with scale, treat it promptly & examine its neighbors.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)