The next time you need to clean the gutters at home and don't want to get the ladder out, try standing on the NFL rule book.

The PDF version available for download at the league's website runs "only" 104 pages, but don't fret. The rule book is already so dense in spots it makes concrete seem porous, and it's only going to get thicker. A joke making the rounds even now is that linemen are skipping bench-presses in the weight room and sleeping with a copy on their chests at night instead.

Since nobody was perfect the last time we checked, it's no wonder NFL referees still get it wrong on occasion. That's despite being backed up by six of their brethren on the field, a TV audience numbering in the millions and a state-of-the-art video replay command center at league headquarters that would turn the folks at Homeland Security green with envy.

Even smaller wonder, then, that coaches, players and fans still go nuts when those blunders happen near the end of showcase events — as they did in the last two "Monday Night Football" games.

A wrong-headed interpretation of the "batted ball" rule in the Detroit at Seattle game on Oct. 5 probably cost the Lions a win and almost certainly saved Seattle's season. A clock operator's error in the Pittsburgh at San Diego game last Monday night left the Steelers with enough time to complete the winning drive. But it also resulted in the suspension of the side judge who was responsible for supervising the clock.

To be fair, the NFL quickly owned up to the mistakes in both instances. But that's gone only so far in calming jangled nerves.

"Ultimately, the key is to get the call right," said Mike Pereira, a former ref who went on to supervise the league's officials and now works as a rules analyst for Fox Sports. "It's just: How far do you want to go in terms of taking the game off the field, into the press box, into New York? How far do you want to go to get that call right?"

Fair question.

NFL spokesman Michael Signora said Thursday there have been 139 stoppages for instant-replay reviews this season. On 66 of those occasions — or 47.4 percent — the on-field ruling was overturned. That's why some coaches, most notably the Patriots' maniacally meticulous Bill Belichick, have advocated employing the review system on every play.

But here's a reminder to be careful what you wish for: While the average time spent on each review has gone down — from 3 minutes, 59 seconds in 2013 to 3:37 last season — the amount of live action in a typical three-hour telecast is still 14 minutes or so.

As Pereira noted above, more study time will give replay officials the chance to be more accurate, but it will also lead to even more standing around. On top of that, too many of the improvements in technology have required revising or re-interpreting rules that were already in place — remember the brouhaha over the "tuck rule" — and the law of unintended consequences guarantees that process will continue hand-in-hand forever.

So long story short: Get used to it. And if you insist on finding someone to blame, might as well start at the top. This is a problem of the NFL's making.

Instant replay was first introduced in a regular-season game in 1986, then banished by a vote among the owners in 1991 after a league study determined it was effectively a waste of time. Only 13 percent of all the calls made over those six seasons were reversed after a replay and making matters worse, 10 percent of those reversals were deemed to be incorrect.

"Basically," said Norman Braman, the Eagles owner at the time, "it was a great theory that didn't work in practice."

It still doesn't, frankly, and there's bound to be errors so long as humans make the first call and — no matter how much technology is employed in the steps in-between — the last one.

Despite that, the league's competition committee kept proposing revisions to address the concerns of owners and coaches, and the instant replay returned with a vengeance heading into the 1999 season. Although the NFL has spared no expense since, and the system is demonstrably better and less time-consuming, it's always going to be a work in progress.

For a while, fans held out hope that improving the human component — making NFL refs full-time employees, paying them more and subjecting them to even more reviews, refresher courses and clinics — was the answer. Unfortunately, that dream was crushed years ago, during one of the more contentious negotiations with the refs union.

That's when the late Art Modell, a crusty sort who owned the Browns at the time, threw up his hands and asked, "I just want to know what they're going to do for five days a week — eye exercises?"