Everybody else seems to be in spring cleaning mode, so this is a good time to once again clear out the ratings notebook:

One year later, who would have thought NBC would be clamoring for the ratings of “Law & Order: Trial by Jury”?

Well, after two weeks, the new 10 p.m. legal skein “Conviction” has averaged a measly 3.0 rating in adults 18-49, down 37% from the initial airings of Dick Wolf’s “TBJ” in the same Friday-at-10 slot (4.1), according to Nielsen.

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The “Conviction” numbers are especially dreary given the boost that “Deal or No Deal” has given NBC on Friday.

On the first two nights “Conviction” aired, NBC led in 18-49 at 8 with “Deal” (3.8 average) and at 9 with “Las Vegas” (3.4).

“Deal” is airing regularly on both Monday and Friday, but also will play on a couple of Wednesdays to help lift that night’s rejiggered lineup.

Peacock will be criticized by some for relying too much on the Howie Mandel-fronted skein, but why not ride a hot horse? The net is really struggling otherwise, and it could use the gamer to call attention to other shows.

However, if it shines a light on shows that viewers don’t want to see, then it’s a waste.

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Through its first two months this season, Fox devoted a whopping 1,600 minutes to “American Idol,” a increase of 37% (or 7½ hours) over last year’s 1,172 minutes.

You can’t blame Fox for milking every last minute, though, as the music competish is remarkably outperforming last year by 11% in 18-49. Still, you wonder if viewer fatigue will set in at some point.

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One of the effects on the competish of so much “Idol” is that the show is now invading more and more time periods — and wreaking havoc on its inhabitants.

It’s already put a dent in ABC’s “Lost” on Wednesday and CBS’ “Survivor” on Thursday, and it’s been brutal for any competing comedies.

Pity ABC’s new Tuesday comedy “Sons & Daughters,” which opened to decent numbers opposite “House” a couple of weeks ago (3.3 average in 18-49), only to get flattened (1.9) when “Idol” expanded to two hours.

There’s no pity over at CBS, though, where the new military action drama “The Unit” has held up very well in the Tuesday-at-9 hour; similarly, numbers for “NCIS” at 8 have been virtually unaffected by the presence of “Idol.”

Through its first two airings, “The Unit” has averaged a potent 4.9 rating in adults 18-49 and 18.3 million total viewers, becoming the most impressive new drama performer of the season.

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Back to “Sons & Daughters,” and for that matter NBC’s “The Office”: Why can’t their respective nets showcase these offbeat, fragile shows on Saturday?

Imagine, for example, a two-hour NBC Saturday block during the month of April with back-to-back episodes of the workplace comedy from 9 to 11. Worst-case scenario, it does a 1.4 rating (as opposed to a 1.8 for the net’s tired drama repeats).

But there is tremendous upside in attracting new viewers, and block programming is a great way to get their attention.

NBC’s patience with “The Office” has been rewarded with higher ratings, but a comedy that airs against “CSI” could always use more exposure on a night like Saturday.

ABC similarly should give “Sons” a shot on either Friday or Saturday. This is one ABC comedy that deserves to be on the sked next fall, and it will only get there if more people have a chance to sample it.