You should invest as much into accessibility as you do into scaling. Meaning: you should think about it early on, and design for the need, but not over invest

You should invest as much into accessibility as you do into scaling. Meaning: you should think about it early on, and design for the need, but not over invest in it too early. If you're at the the stage where you don't know if your idea will work, you shouldn't be polishing accessibility, just like you shouldn't be denormalizing your database schema to increase performance. However, you should be thinking about accessibility, just like you should be thinking about how your database queries will scale if you get increased load. So for example: if you're making a database of images, why not add a field for alt text from the start and start populating it now? If your app needs drag and drop, why not start sketching out an alternative flow for people who can't drag and drop now?