Let’s start right off with why it is so important to have deadlines other than the obvious.
The obvious being the deadline ensures on-time completion of the designing part, leads to a smooth workflow. Additionally, when you work with deadlines, you get time to work on your mistakes as well, and thus you are able to deliver appropriate work to your client.
The not so obvious is what it does for you mentally.
A perk to this job is that you can essentially do it from anywhere, and you don’t need to be tied down to an office space.
Meaning that you have the ability to do this job in the places you find the most comfortable to work, but some people have a hard time with the discipline that is needed to effectively produce results when they are in a relaxed state.
Having a deadline keeps you in check when you have to have certain parts of the process completed before the next person in development can being.
Nothing like being held accountable for why a launch was delayed.
The deadline also allows you to have creative freedom as the designer while the client will have plenty of time to make any adjustments or corrections to your work.
When you have the creative freedom that can allow you to do some pretty awesome things but staying within the constraints of time keeps you from doubting your ability to give the client exactly what they are looking for.