ime weekend searches tend to generate higher-priced results than midweek searches, but that could be related to the routes (mainly WAS<-->LAX/SEA) and travel days that I'm searching; as far as year-to-year and/or month-to-month price comparisons, I've seen some fluctuations
one example that comes immediately to mind is an FCM fare, BWI-SEA on a Thurs morning: Oct 2014 $601 (booked ~T-72, lowest available all day), Oct 2015 $492 (booked over MSP at T-24, immediately SDCd to the 36J 763 over ATL; T-12 for that flight, which was selling at $1400+), Sep 2016 $624 (booked a couple days ago; various sub-$500 options were available, but I'm not going to mess around with SDC for the 744)