Despite the Korean War lasting only three years, the television show M*A*S*H was on the air for an incredible 11 seasons. Since going off the air in 1983, the show still runs in nearly every country, attracting olds fans and new ones along the way.
M*A*S*H can be split up into three eras. The first era, Seasons One to Four, was inspired and, by many, considered the highpoint of the show. The second era, Seasons Five to Eight, delved deeper into the characters, showing them as human and fallible. The third era, Seasons Nine to Eleven, were, at best, trying really hard to remain in the mold that was expected of it; succeeding in drama, but failing in humor and, occasionally, plausible storylines.
In the opening credits, look for the names McLean Stevenson and Wayne Rogers. If you see these, you are watching one of the first three seasons. Both actors left the show before the fourth season.
Step3
In the opening credits, look for Gary Burghoff’s name. Gary Burghoff left the show during season Eight. If you see his name preceded by Larry Linville and Harry Morgan, you are within seasons Four and Five. If Larry Linville’s name is replaced by David Ogden Stiers, you are within seasons Six and Eight.
Step4
Pay attention how Hawkeye interacts with Major Margaret Houlihan. Is there some animosity, some loud disagreements? Does he call her Major or Hot Lips? If so, you are within the first five seasons. If she is referred to as Margaret, know that you’ve passed into seasons Six and beyond.
Step5
Pay attention to where everyone sits in the mess tent. Is every major character, despite their liking one another or not, sitting together as though no one else in the camp exists? If so, you might be watching any season after Seven.
Step6
Pay attention to Margaret’s hair. Is it pulled back into a tight and rigid bun? If so, you are watching an early season. Is her hair feathered? If so, you are watching one of the later seasons. Apparently, just like the later seasons of Happy Days, the actors just stopped pretending they were supposed to be in a different time period.
Step7
Pay close attention to the plot. Is it kind of ridiculous (i.e. is there an indoor bowling tournament? Does it revolve around the camp newspaper having too many editors?) to the point where you wonder why they even bothered? If so, you are watching one of the later episodes. The sub-plot to this episode is probably a good one, but you must suffer through the main plot line.
Step8
Take a quick look at Klinger. Is Klinger dressed up in women’s clothing? If so, you are watching any of the first seven seasons. Is Klinger wearing a Mudhens baseball jersey and cap? If so, you are watching one of the later seasons after Klinger takes over Radar’s job as company clerk, becoming less of a pacifist wanting to be sent home and more of a get rich quick sort of cliché.
Tips & Warnings
If you happen to sit down and watch an episode of MASH at random, this will hopefully help you determine what era you are watching and, therefore, give you an idea of you might expect from the next half hour of your life.
Enthusiast 
