Since 2007-2008
2007-2008: got off to a historic start, looking unbeatable, only to collapse, squeak into the playoffs, swept by Pittsburgh,
2008-2009: Miss the playoffs
2009-2010: decent year, make the playoffs as the 5th seed thanks to 10~ game winning streak, lose to Pittsburgh in 6
2010-2011: one of the worst teams in the league, acquire Anderson, and we end finishing 26th (New Jersey won the lottery, moving from pick 8 to pick 4, bumping the sens to pick 6, which was Zibanejad)
2011-2012: low expectations, peksy sens emerge, we unexpectedly make the playoffs, lose the NYR in 7
2012-2013: lockout shortened year, we lose everyone, karlsson, Anderson, Spezza, among others, still make the playoffs, knock off Montreal in a spectacular series, lose to Pittsburgh in the round 2
2013-2014: miss the playoffs, I literally don’t remember anything from this season.
2014-2015: start the year horribly, and go on the historic hamburglar run to make the playoffs, go down 3-0 to Montreal, start to claw our way back, early whilstle negates a tying goal, series over
2015-2016: inconsistent, leaky defence, miss the playoffs
2016-2017: boucher comes in, brings his (in)famous defensive approach, many things glue the team together, go on the playoff run
2017-2018: no comment
So all in all, no one knows what the sens will do in any given season. If they finish atop the division or at the bottom next season, neither would surprise me anymore.