indeed it is subjective. it varies between persons, and for the same person it varies between tasks.
i use 4x2 24" in the office. some days it feels like i could use more screen space. but it has also reached a point i need to roll back and forth on my desk to read all ends. coding work is concentrated in 3.5 screens. spreadsheets, browsers, email, front ends, other software occupy the rest. and yet it still hasn't released me from alt-tab hell. there will always be that bunch of information that you must have in front of you no matter the cost, and the cost is that you still have to alt tab the less important windows -email, excel, hacker news.
i use 4x2 24" in the office. some days it feels like i could use more screen space. but it has also reached a point i need to roll back and forth on my desk to read all ends. coding work is concentrated in 3.5 screens. spreadsheets, browsers, email, front ends, other software occupy the rest. and yet it still hasn't released me from alt-tab hell. there will always be that bunch of information that you must have in front of you no matter the cost, and the cost is that you still have to alt tab the less important windows -email, excel, hacker news.