Is your clothes dryer working properly?

Maybe. If you notice it takes longer & longer to dry your clothes there may be a problem. Likely the problem is lint blockage in the exhaust system. When running the dryer check flow at the vent on the outside wall. The vent flap should be open and a fair amount of warm air should be blowing out. If not the next task will be to pull the dryer  away from the wall and check the exhaust system for blockage. Your system could be clogged with lint, which is potential fire hazard. It was as if someone has stuffed tons of lint into the duct with a cannon ram. Actually, the system could be blocked anywhere along the line many times in the crawl space. Flexible duct is prone to blockage, use rigid where possible with metal tape, not screws. The run should be straight as possible and insulated in any unheated area. The exterior cover should free of vegetation or other blockage.