Almost all of the law firm research surveys are conducted once a year. The effort is considerable and firms want to allow sufficient time to pass, especially if they are conducting a series, for changes to appear in the data. Annual surveys rule. That said, at least three law firms have conducted surveys on twice yearly.
Irwin Mitchell Occupiers 2015 [pg. 3] is one of the reports that has gathered data in the Spring and Fall regarding office rentals.
Morrison Foerster MA Two 2017 [pg. 3] reflects surveys that collect input in April and then in September.
Haynes Boone Borrowing 2016 [pg. 2] represents one of a series that gathered data on borrowing practices in April and September.