The size of the project truly matters in this discussion.
If I anticipate to work with a client for long-term, then I would usually be alright with providing work before getting paid. Better yet, the 50-50 method wherein the client gives a 50% down payment also works. If I perceive a potential client to be one that I stick with, then I would be generally alright with being patient, especially if it's already their typical payment scheme for other writers. As long as they keep giving me the income that I expect, then there shouldn't be an issue concerning such.
However, when there are shorter projects, then I would expect that the payment would be upfront. There shouldn't be a reason for a client to not provide this, especially because shorter projects usually also indicates that they need to pay me less than they would if it was a massive one.
If I'm being asked to deliver a rush order, then, of course, it will only be wise to ask for a payment upfront. Typically in the industry, papers to be delivered within a shorter time frame are more expensive because it requires a tremendous amount of effort and time from the writer. Therefore, writers should be cautious of having an equitable relationship with their clients in these instances because the probability of being scammed can be higher (due to how expensive the entire project would be).