Discussion on question by python_user: Should I quit my job if I am taking over a bad code base with not so good support from the original creators?

Cleaning up a mess created by others comes with the territory. Basically you have to inflate your estimates of feature addition and do a little cleanup each time you do something else. That's an essential part of what they're paying you for (attending to client/employer needs in a professional way), even if they don't understand the necessity of it. Most likely they do understand just fine, but have overriding business concerns, making this a classic urgent-vs-important case.

actually HERE is the canonical answer, @python_user ! enjoy! workplace.stackexchange.com/a/169647/22844

@python_user Don't worry, the code you write now will be someone else's misery in 5 years time :) That's what happens in a fast moving industry.

My manager did agree on letting me re write the code but only after I complete my current backlog your backlog will never be empty. Make small improvements when and where you can as you work on the backlog. That is the only way.