Lug nuts are handled differently at almost every garage. If you've experienced a lug that is extremely hard to loosen they were likely tightened with an impact tool. There is a device called a torque stick which can make pneumatic tools much more effective at avoiding over-torque. In most every shop, I see impact tools used, while I often do not see torque sticks. Maybe this is just my luck, or possibly I've only seen a small sample of garages.
I take lug nut torque responsibility into my own hands, literally. When one torques a lug nut or bolt, they're effectively stretching the lug stud or bolt. This is why I recommend always using the lug torque specified in your vehicle's owner's manual and tightening lugs in a crisscross sequence. To gain a better understanding of how to properly tighten and loosen your vehicle's lug hardware, read "Wheel Lug Torquing."
To keep the lugs moving like new on my vehicle, I clean the corrosion off of them with a wire brush. Speaking of new wheels, always make sure to re-torque them after the first twenty miles of driving.
The most effective way to set your lug torque is with a torque wrench.
The Tire Rack Adjustable Torque Wrench is great for handling tire and wheel duties. I'm going on my tenth year with the tool which equals approximately $4 a year (wrench cost me around $40) to have the correct torque settings.
When the time comes to break lugs loose, use a breaker bar. Personally, I carry the Gorilla Extendable Power Wrench in every one of my vehicles as it's easier to work with than stock lug wrenches for roadside tire changes.