I only ask because I've heard that your agent and publisher will want a book a year, or at least a book every year and a half. Do you think you could manage that? It took my about 6 months to complete my current novel, LORNA, which is about 96,000 words, so I think I should manage it. But I know some writers spend a long time on editing and subsequent drafts etc.
Depends on the contract you sign with the publisher. Most 'romance'-style houses ask their authors to produce a book or more a year. Mostly, a year remains standard if you write commercial or mainstream fiction.
Again, that's standard.
However, if you write historical fiction or something more detailed, it's not standard. The agent and publisher know that a poorly written, yet quickly written novel, loses more money than a novel well-written, and slowly written, over time. That's because the reviews for your poorly written novel will hurt the sales for your next novel.
You're only as good as your last book.
That's not to say some authors, who will remain nameless, churn out tripe because their fans will buy anything with the author's name on it no matter how awful it reads. It's a sad state, but bulk often outshines style when it comes to profit and the gory business we call the name-game.
That's another topic though.
Personally, to answer your question, I can write a standard novel in one to three months. That's the plot, theme, and characters. To polish to my standard, I'll take a year for the edits and rewrites. This time includes side projects like short stories, articles, and other related media. But, to be honest, I usually have four or more books on the burner. I do this because if a project fizzles, and it happens, you can still use good material from the 'flop' and salvage it into a bestseller.
One book, I'm still writing, has taken four years between other projects. If it takes longer, so be it. I'm not releasing garbage just to pay the bills as some of my peers have done. Again, no names mentioned.
But, I will say this: Your readership will wan if you take too long between novels. So be careful not to dangle the carrot with a stick more like a tree. They find someone else to read otherwise.