It definitely depends on the job. When we are hiring anyone with content creation as a key part of the role, we do ask candidates to submit writing prompts as part of the interview process. Much like Arika described, it's always a real-world exercise to help us gauge someone's creativity, writing quality, and ability to take feedback. Done well, a writing prompt should give you an expected timeframe to invest in completion; if not, it's completely appropriate to ask for guidance from HR or your hiring contact. When you send in your submission, you can also note how much time you actually spent, as a way to indicate the level of effort reflected by the deliverable. And, yes -- follow Arika here too: if you have samples already, definitely offer those up first! We've waived the writing prompt part of the interview for candidates with great samples already.