In 1987 SST Records purchased the Descendents' former label New Alliance Records, re-releasing all of their previous albums and releasing the new album All. The Descendents performed a final tour later that year, marking singer Milo Aukerman's departure from the band to pursue a career in biochemistry. The band then recruited singer Dave Smalley and changed their name to All, continuing to record for SST. Two Things at Once was released in 1988, combining all of the Descendents' recorded output from 1979 to 1982 in a single release.
Mike DaRonco of Allmusic gave Two Things at Once four stars out of five, saying that "All that mischievous teenage skaters could appreciate is here, classics like 'Myage,' 'I'm Not a Loser,' 'Bikeage,' and 'Hope.' But for all those who already own their "best of" (Somery, which features the previously mentioned songs), other less-known hits such as 'Marriage,' 'I'm Not a Punk,' and 'Catalina' are exclusive to this release." Jenny Eliscu of Rolling Stone called the album "an essential introduction to the group."