Members of Congress have a pretty high-status job-- and most of them don't retire until they're soiling adult diapers. But there are various reasons-- and combinations of reasons-- that cause members to throw in the hat earlier. Many like going to a far less status positions at lobbying firms, where they can make immense amounts of money using their connections with their old colleagues to push corporate agendas. Another reason is to run for higher office. So far this year, seditionist Mo Brooks (R-AL), careerist Tim Ryan (D-OH) and loony extremist Ted Budd (R-NC) are giving up their House districts to run for Senate seats. Brooks is a shoo-in; Ryan has a so-so shot and Budd has no chance at all. Then we have Charlie Crist (Blue Dog and "ex"-Republican-FL) and Lee Zeldin (R-NY) running for governor and far right extremist nut-bag Jody Hice (R-GA) running for Secretary of State.
Aside from members who have died, 3 Democrats and 1 Republican just gave up right after being reelected, leaving their seats empty and their constituents in a lurch. Cedric Richmond (New Dem-LA), Marcia Fudge (D-OH) and Debra Haaland (D-NM) took jobs in the Biden administration and Steve Stiver (R-OH), fed up with Trumpism, took a job as CEO of the Ohio Chamber of Commerce (basically a puffed up lobbying job).
This week, octogenarian Pat Leahy (D-VT), first elected in 1974, told his colleagues he's running again-- and claims that he's the only Democrat that can win the D+15 seat where Biden beat Trump 242,820 (66.1%) to 112,704 (30.7%), Biden's strongest showing in the country winning every county but Vermont's politically backward, sparsely populated Essex County. Last time Leahy faced the voters, he also won every county but Essex... and clobbered Republican Scott Milne 61.3% to 33.0%. A Republican senator he works closely with, likely Richard Shelby (R-AL), noted that he "always assumed [Leahy] would run simply because: What else would he do that he’d like better than this?"
That means all 5 senators who have announced they're not running again are Republicans-- the aforementioned Richard Shelby (R-AL), Richard Burr (R-NC), Pat Toomey (R-PA). Rob Portman (R-OH) and Roy Blunt (R-MO). Chuck Grassley (R-IA) is around 200 and hasn't announced a decision yet.
So far 6 House members have announced they are retiring from public life altogether, not seeking reelection to their House seats and not seeking election to anything else. Ann Kirkpatrick (New Dem-AZ) has come out as an alcoholic. Tom Reed (R-NY) has admitted sexual harassment. Eddie Bernice Johnson (D-TX) is senile and no longer functioning but always says she's retiring and then decides to run anyway. Kevin Brady (R-TX) is 66 and would be losing his position as top Republican on the Appropriations Committee if he was reelected. Cheri Bustos (Blue Dog-IL) and Filemón Vela (Blue Dog-TX), who always wanted to be a lobbyist anyway, both saw their districts' PVIs sink into difficult red territory and Vela's district is likely to be gerrymandered into something friendlier to Republicans.
Tim Ryan's district went from D+7 to D+1 an R+6.1 shift. Vela's district went from D+10 to D+5,a downward shift of 4.8 in favor of the GOP, largely because Vela never does anything involving participatory democracy-- like many other Texas Democrats in safe seats, who could have swung their districts more strongly to Biden and possibly won the state. Congress-- and Texas-- will be far better off without Vela.
Bustos' district went from a D+3 to an R+2, an R+4.8 shift. And Robin Kelly, the new head of the Democratic Party, hates her and would have been unlikely to do much to help shore her up. Trump won the district in 2016 (47.4% to 46.7%) and then again last year (49.7% to 48.1%). In 2016, Bustos won reelection with a strong 60% of the vote but last year she only managed a narrow win against Republican Esther King (who is running again), 156,011 (52.0%) to 143,863 (48.0%). And her path to higher office in Congress-- she was certain she would be speaker-- collapsed after her abysmal showing as DCCC chair in 2020.
Other possible House retirements include Florida conservative Democrats Val Demings and Stephanie Murphy, both supposedly eyeing the state's Senate seat occupied by Marco Rubio. Two others wretched conservative Democrats, Iowa's Cindy Axne and Pennsylvania's Conor Lamb are close to announcing for Senate races, especially Lamb, who is already secretly running-- asking right-leaning donors to help finance his campaign. Republicans Andy Biggs, an Arizona insurrectionist, and Mike Turner, an Ohio mainstream conservative, are also looking seriously at higher office.
Turner's district has become slightly redder. Bigg's district is still blood red (R+11) but less so than last cycle (R+15). Axne's district has become redder-- from R+1 when she first won, to R+3 now. Conor Lamb's district has also slipped a little redder, form R+1 to R+2. Val Demings' district is safely blue at D+12, up from D+11 and Stephanie Murphy's district went from an even PVI to a much safer D+3.