My home is built, is it too late for a central vacuum system?

The quick answer is no, it's not too late. Many installers of
central vacuums have become very creative on where they run the
tubing. They work around the house through the attic, basement
and garage, then drop the tubing down behind the interior walls
from the attic or push it up from the basement. In some
instances they may use a cold air return to get the tubing to
the proper location. After the central vacuum system is
installed you will be amazed at where they can get the tubing
without any visible signs of damage.

Tubing is run throughout your home with outlets spaced out
approximately every 750sq.ft. of floor area. Some considerations
when installing the outlet is the location of furniture,
appliances and general convenience. Typically it is best to
start the outlet installation at the farthest location away from
the canister, and then work back towards the canister. 

In many cases the canister is located in either the basement of
the garage. Common sizes of canisters are 6 and 7 gallon. Most
manufactures offer both bag and bag less canisters, both types
work very well. Under normal use you may only empty the canister
or take the bag out every 3 or 4 months. 

There is a higher cost to installing central vacuums into a home
that is completed as opposed to installing the system as the
home is being built. Since the cost is substantially more than
your traditional upright or canister style vacuum cleaner, it
would be wise to ensure that it has a very good warranty
service. I would recommend that you have a professional install
the central vacuum system, as well get at least three quotes for
the job.