You've asked the questions, and here are my professional answers.

Question: Do I need to have my dryer vent cleaned?
Answer: Yes. Dryers produce lint which is very combustable.
However when to have it cleaned depends on the amount
of usage and type of clothes your drying. If you find
that your clothes are taking longer to dry than normal
or if you see excessive lint hanging out of your vent
hood or around the bottom of dryer it is time to have
it cleaned. Dryers have a flame which is located close
to the floor so it is important to keep the area clean.
Also a clean dryer not only dries clothes a lot quicker but with lower fuel consumption.

Question: Why do you feature air conditioning in the winter?
Answer: Because winter is the best time to install air
conditioning. In the summer attics become to
hot to work in, also as soon as it gets hazy
hot and humid people realize that they want air
conditioning only to find Contractors are back
logged to get it done in time. Colder weather is
the optimum time to install your system.