Air Conditioner is Not Working

I have come home from the holiday to find my central air conditioner has leaked down again...and this is the last time I plan on dealing with this.


-what is the rule of thumb for sizing central air conditioners?

-I do not know who is good and who is not in my town...is there some kind of on-line rating service (like yelp) that I can use to find reputable installers in my town?

-I have seen people say that the skill of the installer affects the dependability of the unit later on...what are the factors that I should look for in the installation to be sure I am getting the best job that I can get?...

- what seer rating should I choose?....