Always having your laptop plugged in will keep it from going through cycles.
In saying that, after 329 cycles and 28months, I still have 95-98% of battery life, depending on the day I calibrate it....
It fluctuates, and the readings aren't always 100% accurate.
For the price of the battery, and how long it lasts, just use it as you need to, and keep it plugged in as often as you can.
Some have a better battery performance than others, but at the end of the day, in most cases, the battery will last most the life of the laptop, if not all of the life, or until you are ready to upgrade to a newer model