I used the workbook for Quartet 1, but didn’t find it useful enough to buy the workbook for Quartet 2.
The reading section was really helpful, it had trick questions so it forced you to really understand the readings.
The grammar section was frustrating, it’s pretty much just half-written sentences that you have to fill out with the requested grammar points, but figuring out what the sentence is supposed to end up saying, and how exactly they expect you to use the grammar point, was more trouble than it was worth. You’re better off writing your own sentences and getting them corrected, or using Bunpro.
And there’s no extra listening for the already-too-short listening section in the textbook.
So if you decide not to get it, you’re not missing much.
I got the workbooks for both parts of Quartet, and while I wouldn’t say they’re absolute must-haves, for me, they fulfill a pretty essential role. The workbook forces me to actually interact with the content of the textbook - without the workbooks, I would probably just do the bare minimum of reading through the textbook lessons and then forget them right away,
