IT’S always interesting being a coach or a manager in the big city, just never more so than now, in a 24-7 sports culture in which a coach or a manager can go from messiah to pariah in the course of an overnight show.

We happen to live in a time when all seven stages on the Coaching Scale are occupied by present members of the New York coaching/managing fraternity. It’s good to flash-freeze a list like this, because these placements always can change depending on the next hit-and-run call or the next power-play shift.

But for now, the final Sunday of April in the year 2008, here is that Seven-Point Coaching Scale ranked from highest to lowest and everywhere in between:

1. Bulletproof – Tom Coughlin: Which only proves just how fickle these scales can be, because Coughlin has occupied every one of them in the past four years. Hell, he just about occupied all of them last year alone. But he, and he alone, belongs here because he is sitting on the Perfect Storm of coaching job security: He coaches the reigning champions. He has a brand-new contract worth millions. He has reinvented himself into a player’s coach, and he has players who have been perfectly willing to extol those virtues ever since they proved to be real. This is the level all coaches aspire to, and few are able to keep for long. Two years ago, Willie Randolph sat here. Seven years ago, not only was Joe Torre locked in here, it was hard to believe he would ever get evicted. He was. It happens. To all of them, eventually.

2. Untouchable – The Next Knicks Coach: If you aren’t going to have a big gaudy ring to flash around, you do well to have the next best thing: an unspoken-for, unintruded-upon future around which to sell yourself, coupled with the reality that it is mathematically impossible to do any worse than your predecessor did. This is even better than the various honeymoon phases to follow, because there isn’t even a small sample in which to alter the data. If we all accept one of the bedrock truths of sports to be that managers and coaches are hired to be fired, we also can accept this dangling corollary: The one day they can avoid worrying about getting fired, maybe the only day, is the day they’re hired. Or, better still: the days before they’re hired.

3. Untouchable, For Now – Tom Renney: The last two words are the most important, because as we know, nothing lasts forever. But Renney has done what seemed like an impossible, unmanageable task: he not only has built a winning culture at Madison Square Garden, he did it with the Rangers, who spent close to a full decade wandering in the kind of pathetic wilderness even the Knicks haven’t quite reached yet. This always can change. The Rangers could lay a giant egg against the Penguins, they could start slowly out of the gate next year, fans could start chanting derisively, players could revolt, on and on and on. It’s all part of the balancing act, all part of the challenge. Just not an immediate worry. For now.

4. Honeymoon – Joe Girardi: Here’s the beauty of The Scale. If you are Bulletproof, then when you choose to pitch to Manny Ramirez, you are simply showing the kind of faith in your player that made you such an infallible winner. If you are melting on August ice, it proves what a buffoon you are. If you’re on your honeymoon – which is where Girardi is, and will remain all year – you’re taking your lumps, learning from your mistakes.

5. Honeymoon Over – Eric Mangini: Here’s the thing, though: don’t plan on spending too much time in Maui on that honeymoon. Here’s the bane of The Scale: if the Jets had gone 4-12 in Mangini’s first year and 10-6 in his second, he would have one foot in Coughlinville. But Mangini got it backward. His 10-6 rookie season got him a spot on “The Sopranos,” and at the time it would have been impossible to think about the ironic possibility of him soon getting whacked, too. Yet less than a year later, the bloom isn’t merely off the rose, the rose is wilting. And that’s not just a talking fish saying so, either.

6. Touchable – Willie Randolph: It’s easy to rip the impatience of Mets fans, mostly because it’s so easy sometimes to rip Mets fans, period. But the notion that Randolph could be managing his way onto someone’s third-base lines before long isn’t as outrageous as some would think. He did an A-plus job in 2005, an A-job in 2006, and a C-minus job last year. That isn’t the kind of performance arrow that solidifies a man’s job security.

7. Ice in August – Lawrence Frank: He has powerful allies, and those are good things to have, especially when you won the first 13 games of your career as a head coach and have gone 178-177 in the ensuing 355. It would behoove young master Lawrence to win a few basketball games next season, and quickly. Because the next spot on The Scale is a spot off The Scale. And out of work.

Mike Vaccaro’s e-mail address is michael.vaccaro@nypost.com. His book, “1941: The Greatest Year in Sports,” is available in bookstores.

VAC’S WHACKS

Anyone who ever questions the wisdom of treating young arms like precious metal need only refer to the sad case of Francisco Liriano, his 11.32 ERA and his current mailing address of Rochester, N.Y.

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Marty Brodeur has long been one of the most decorated and best-credentialed residents of our humble sporting region, and he will be one of the easiest first-ballot Hall of Fame picks in any sport. But it was a D-minus move by an A-plus player to snub Sean Avery that way, no matter how much Avery might have had it coming.

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Thank goodness for Kellerman and Kenny on 1050, who do like to remind you now and again that you don’t always have to treat sports as High Mass to get your point across. Witness: the hysterical “Typical Football Analyst Guy” bit.

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Is it just me or has Hillary-Barack officially turned into one of those six-overtime NHL playoff games that stops being thrilling and bleeds into tedious right around the third OT? Can’t one of these two just bounce one in off someone’s skate and be done with it already?