GREEN BAY, Wis. -- Think about what it’s like to do the same job over and over, year after year.

The history teacher who digs out last year’s lesson plans and changes the dates to match the current calendar. The insurance agent who calls policyholders annually to renew their coverage. Even the NFL reporter who writes the same formatted free-agency preview every March, the same draft preview every April and the same position-by-position series every July before training camp.

That’s exactly the kind of mindset that can doom an NFL head coach, at least according to Mike McCarthy.

It’s why the Green Bay Packers' coach, one of the most senior members of his fraternity, doesn’t want Wite-Out, Liquid Paper or any other kind of masking agent anywhere near the coaches’ offices on the third floor of Lambeau Field.

“Well, if you just keep doing the same thing, I mean, we don’t just erase the date and put Wite-Out on it,” McCarthy told reporters last week at the NFL annual meetings in Orlando. “You guys still use Wite-Out in your industry? We don’t just change the date. You always have to improve.

“We’re coaching the millennial generation. These guys want to know the ‘why.’ So you’ve got to tell them not only what we’re doing, why we’re doing it, how we’re going to do it, and continue to get them to invest in the why and be creative and instructive and inspire, and you can’t operate with that mindset doing the same thing all the time.”

'A scrub-brush approach'

That’s how McCarthy, in preparation for his 13th season as the Packers' coach, described his approach to this offseason when it comes to game plans, practice plans, playbooks and anything else that touches the way his team prepares and plays.

That’s what happens when you miss the playoffs for the first time in nine years.

What began with significant changes to the coaching staff -- chief among them Dom Capers out and Mike Pettine in as defensive coordinator; Edgar Bennett out and Joe Philbin back as offensive coordinator -- turned out to be just the start.

The activities in the coaches’ offices this offseason looked more like they did in 2006, when McCarthy was a first-time head coach.

“This offseason resembles a Year 1 offseason,” McCarthy said. “Obviously the defense is going through that because they’re building a brand-new playbook, new coaching staff, new philosophy. There is some carryover from our old defense. But offensively, when you have the same offensive system for 12 years, you’re playing late into the playoffs, you usually turn the page and evaluate and just try to evolve off what you did last year. We’ve taken a totally different approach. We’ve gone back to Page 1 in the playbook.”

McCarthy said everything was open for discussion -- from the language used in the playbook, to formations, line-of-scrimmage declarations and pre-snap adjustments.

“We’ve taken a scrub-brush approach to the whole system,” McCarthy said.

Working nights and weekends

That has meant long days and long nights in the office for his new staff, which includes passing game and running game coordinators on both sides of the ball.

As McCarthy spoke last week in Orlando, he couldn’t wait to get back to Green Bay. His coaching staff had the week off, but many of them were in the office -- as was McCarthy right up until Good Friday. He wants it all done by the time the players report for the start of the offseason program on April 16.

“I need to get back; I need to get back to Green Bay,” McCarthy said last week. “We’re going to be up against it come April 16.”

Offseason studies have become commonplace for McCarthy and his staff. Last year’s was the “across the hall” project in which the offensive coaches devised a game plan to play against the defense, and vice versa.

This one, however, might have been the most extensive undertaking they've done.

“A lot of nights, a lot of weekends,” McCarthy said. “But I still have my routine, swing through the personnel department once or twice a day and visit with [new general manager] Brian Gutekunst, but we’ve really had our nose down to the grindstone, particularly on offense. Because we’ve gone back to a lot of things we’ve done in the past.”

A hard offseason

This offseason hasn’t been the easiest on the 54-year-old coach.

He not only revamped his coaching staff but also sat in on the general-manager interviews and dealt with a complete change in the organizational flow chart that has McCarthy and Gutekunst reporting to team president Mark Murphy.

“This has been as hard an offseason as I think I’ve ever been through,” McCarthy said. “From the day the season was over, all the changes, then you have to hire a staff, making that all fit together. You forget how much time and energy goes into the background checks, just trying to talk to so many different people on the phone, and I don’t like talking on the phone to begin with.

“Then to jump in with this new approach with Joe Philbin and [new assistants] Jim Hostler and Frank Cignetti -- these guys all have history in this offense. The best question you can ever ask is 'Why?' Why did this change? Going back through all that. We’re having conversations that the other guys in the room have never heard. That’s a great learning lesson, because when you’re around a place that long and you have coaches leave or move on, the existing coaches are supposed to pass it forward to the new coaches coming in. That probably wasn’t done as well as it could have been. We were able to go in and clean that up. It’s kind of a back-to-basics approach on offense, and defense is obviously is a whole different deal.”