I’m sure I spend about half of my time devoted to writing doing crits for other writers. Is that excessive? I don’t know. I have often thought that if I didn’t spend so much time on them, I could get twice as much writing done. Sometimes I wonder if it’s worth all that time spent on other people’s stories when I have so many of my own that need to be written.
There are reasons many of us spend so much time on things that do not directly contribute to writing stories. Even if you can write two less-well written novels without extensive critiquing for every better-written one that is well critiqued, your only result will be that the rejections come in twice as fast. With few exceptions, one well-written novel will always do better with readers, editors, and agents than several poorly written ones. Editors are not looking for a slew of bad novels, but rather that one that stands out from the sludge pile.
Getting that novel just right involves extensive writing, rewriting, and critiquing.
It would not be fair to accept crits from others while not giving any back. Besides, if you did so, people would eventually stop critting my work. Also, critting other people’s works is not only good for the writer, it gives the critiquer a chance to sample other writing styles and genres. A critique learns as much critting other people’s writing as getting crits.
I’m really not sure how much time other writers spend with critiquing, but I do know it’s very true with critting that if you give you will receive.