Sources
This site does not perform the work it writes about. What it can do is be exact about the rules, and show you where every rule comes from so you can check it yourself. Every requirement, deadline and frequency stated anywhere on this site traces back to one of these.
Clothes dryer fire safety
National Fire Protection Association. The source behind every claim on this site about dryer fire risk and failure to clean as the leading contributing factor.
Chimney inspection levels
Chimney Safety Institute of America. Definitions of Level 1, 2 and 3 inspections.
Regulations change, and local authorities can be stricter than the state. Where this site says a rule varies by town, check with the office named on the page rather than relying on a summary.