TV shows can have varying levels of success, depending on many different factors, including the number of seasons. TV shows are considered successful if they get four or five seasons. However,  the TV shows that manage to surpass 10 seasons are in a league of their own. And earlier this year, Criminal Minds joined this league when they wrapped after a whopping 15 seasons!

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When a show goes on for any number of years, change is inevitable. Writers get switched around, cast members leave or the plot takes a dramatic twist! And Criminal Minds is no different! Here are ten ways that the show has changed from season 1 to season 15.

Team Shuffling

Over the years, the BAU has gone through many shifts in characters. The first major change was when Agent Jaso Gideon left in Season 3 after traumatic events lead him to question his path in life. However, he was replaced by the wonderful Agent Rossi who remained as an important member of the team until the end of the series.

Towards the end of the series, long-time agent, Derek Morgan, after a near-death experience, leaves the BAU in season 11. Feels are guaranteed!

Different Higher Up Barriers

It is often shown throughout the series that the BAU has to answer to many levels of bureaucracy and that it frequently contributes to conflict. For the first 8 seasons of the show, they have to answer to BAU Section Chief, Erin Strauss. She constantly questions the organization and professionalism of the BAU, which mainly leads to conflict between her and Agent Hotchner.

Another prominent antagonist is the FBI's Assistant Director of National Security, Linda Barnes. A power-hungry and ambitious woman, she sets her sights on re-structuring the BAU, which leads to their quasi-disbanding.

Starting Families

Over fifteen years, it's understandable that characters will start branching off to have families. The first to take that step is JJ, who marries detective William Lamontagne and, together, the couple has two sons. In season 11, Derek Morgan marries Savannah Hayes and the pair have a son.

Even some of the smaller characters begin having families throughout the series. Special Agent Kate Callahan, present only in season 10, becomes pregnant and decides to take a year-long maternity leave.

More "Long-Term" Unsubs

Like most procedural crime shows, the series is full of one-off episodes with different unsubs. Criminal Minds, over the years, have dedicated multi-episode arcs to apprehending certain unsubs. The most prominent of these unsubs is George Foyet, otherwise known as the "Boston Reaper". Not only is Foyet a narcissist and a psychopath, but Agent Aaron Hotchner's ex-wife also becomes one of his victims.

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Another prominent multi-arc unsub is Frank Breitkopf. A prolific serial killer and sexual sadist, he who murders Gideon's girlfriend, and then commits suicide with his lover.

Getting Involved In International Affairs

The BAU, throughout the series, has participated in many international cases. The most prominent of these cases is the episode "Beyond Borders" where they assist the International Response Team (IRT) after an American family goes missing in Barbados. This episode also served as the back-door pilot for the Criminal Minds: Beyond Borders spin-off.

Other examples of the BAU going international is "Machismo", where the team travels to Mexico, and the"To Hell And Back" (Parts 1 and 2), where the team travels to Canada.

Targeting BAU Members

At the start of the series, the BAU is simply solving cases. However, as time goes on, they soon have to start solving cases that involve their members! In Season 3, Penelope Garcia is shot by Jason Clark Battle, a serial killer suffering from Hero Syndrome.

In season 2, Spencer Reid was kidnapped and tortured by Tobias Hankel, which lead to his addiction to Dilaudid. Emily Prentiss even has to fake her death to take down an escaped terrorist, Ian Doyle.

Reid's Confidence Boost

Spencer Reid is very much the team's "nerd". He is shown to be awkward socially and very much leading with his vast intellect. However, over fifteen years, he very quickly comes into his own. In the episode "L.D.S.K", despite struggling to get his gun qualifications, he takes down an unsub with a fatal shot, protecting Hotcher in the process.

Related: Criminal Minds: 10 Most Memorable Unsubs, Ranked

A prominent moment that defines Reid's boost in confidence is in "It Takes A Village". While the team is getting investigated for allowing Ian Doyle to escape. After a Senator tells him to "Calm down, Agent", Reid fires back with "This is calm, and it's Dr.", without even blinking!

Garcia Isn't Always Behind A Desk

Penelope Garcia is the team's resident "tech geek". She is the backbone of the team, as she can track down criminal records, prominent events and other clues to help the team target an unsub. All this from behind a desk!

However, she isn't always behind a desk. She has since gained field experience, after accompanying Agent Simmons to track down serial killer Peter Lewis, a.k.a Mr. Scratch. She also protects Reid by shooting an assassin that is sent after him.

Back Door Pilots To Spin-Offs

A prominent moniker of a TV show's success is when spin-offs within the universe are greenlit. And Criminal Minds spawned two of those! The first was Criminal Minds: Suspect Behavior, which had a backdoor pilot in season 5. It focused on a "Red Cell" team, which answered directly to the FBI Director.

The second was Criminal Minds: Beyond Borders, which had a backdoor pilot in season 10, focusing on the IRT and their efforts to protect American citizens abroad. And, as a bonus, there exists a Korean remake of the show called 크리미널 마인드 (Criminal Minds Korea).

Hotchner Becomes A Better Father

"Family" is a prominent theme throughout the series, not only within the team but within the individual member's lives. Agent Aaron Hotchner has had the most growth in this department. After countless demonstrations that he was married to his work, his wife, Hayley, left him, along with their son, Jack.

After her horrific murder, Hotch is forced into the driver's seat of "parent". He constantly worries about his son's well-being, including an incident when Jack is being bullied at school. His character departure also involves protecting his son from Peter Lewis, as they both enter a Witness Protect Program.

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