!rant Question: How reasonable is it to expect payment before deployment of code to the live instance, even if the project launch was significantly delayed?

-4000%

Chance of getting paid at all if you even ask: -2417%

This shit is best written in the terms of your contract if thats what you want to happen, otherwise they think you are a twat and become agitated and see it as some kind of blackmail. Clients are cunts so best avoid situations if you can get them signed on paper before hand. Also helps when you sue them.

In my case I wrote a 20 page SOW that they signed. The custom software that was part of it was soon overwhelming because of scope change and scope creep. It's partly my fault for not saying "no" and asking for amendments with additional costing but I'm also a one man "agency" trying to build enough income to grow a contract team to full time, so I don't have a lot of wiggle room for that kind of posturing. But now, after all the crap they put me through, I feel I need to draw my line or risk being taken advantage of further with more scope creep after the fact.

@stackodev I'm a one man band, you can't afford to cut corners with proper process. You should always stop and re-evaluate with scope change, always have a contract as well as SOW. Do it properly from the start, I guess I too learnt the hard way but there is really no excuse. Good contracts for web dev here (amongst other things)
https://www.hellobonsai.com/

If it's in your contract then it's not only reasonable, they have no choice.

@biscuit He has no contract, that's the point. Only a SOW.

Yup. I hadn't known about HelloBonsai at the time. Also, the project requirements were like nailing Jello to a wall. I've never worked on something so squirrelly. It never helps when the product owner refuses to educate herself on even the basic troubles of custom software development and doesn't give the benefit of the doubt when you try to educate her. It's all just "magic" and "why can't you".