I found scale... but only one... now i'm confused

[let_it_grow]

I inspect my plants on a regular basis and one day i found 1 scale on a Phal that i have had for 6+ months. I promptly checked over the entire plant and with a Q-tip and some peroxide i cleaned every inch of every leaf and did not find ANYTHING else. I inspected all my other plans and found nothing. I put the Phal in another room. Fast forward 3 weeks and i have still not found any other scale on any plants. How is it possible that i have a plant for 6+ months and find only 1 scale bug? How long should i continue to inspect. I actually had a nightmare last night that my Paph was in bloom and she was infested with scale. Please help. Is it possible to only have one?