You may have forgotten about “Yes, Dear” (8:30 p.m., CBS), but according to the network, it’s entering its fifth season tonight. How does a comedy this mediocre survive? Does it mean we have four more years to look forward to “Listen Up” and “Still Standing”?

Seriously, doesn’t anything get canceled anymore? Viewers used to complain about shows being canceled too quickly. Now they live through entire seasons. CBS has put only one show — “Center of the Universe” — out of its misery. There will be no second season for UPN’s “Second Time Around.” The WB yanked the “The Mountain.” But did “Big Man on Campus” finish its season, or just disappear? Did anybody watch it at all?

NBC had a lot of deadwood to clear, so “LAX,” “Father of the Pride” and “Hawaii” were jettisoned. Fox fooled around with seasons so short you couldn’t tell if something was canceled or not. Is “Quintuplets” still breathing? It’s pretty clear that “Method & Red” is a goner, but will “North Shore” return? ABC’s reluctance to deep-six “Complete Savages” probably says more about Mel Gibson’s clout both here and in the hereafter than the quality or success of his “Complete” atrocity.

Tonight’s other highlights

• Scheduled on “60 Minutes” (7 p.m., CBS): the ongoing controversy over Jose Canseco’s allegations of widespread steroid use among baseball players.
• A nightmare out of a fairy tale on “Medium” (7 p.m., NBC).
• A story, a mystery and a boar on “Lost” (7 p.m., ABC).
• Sparks fly at the New Hampshire primary on “The West Wing” (8 p.m., NBC).
• Hollywood competition continues on “American Idol” (8 p.m., Fox).
• Heir-heads on “Alias” (8 p.m., ABC).
• The 4-hour documentary “Slavery and the Making of America” (8 p.m., PBS) concludes.
• A bride dies at the altar on “CSI: NY” (9 p.m., CBS).
• An obnoxious fan runs afoul of a basketball player’s temper on “Law & Order” (9 p.m., NBC).
• The Partridge Family goes six feet under as an RV-driving wife trades places with a mortician’s main squeeze on “Wife Swap” (9 p.m., ABC).