I read Tidy First? ―Experiential Software Design for Individuals.
With only 130 pages, it's a quick read.
The book prompts you to consider whether to "tidy up" from the perspectives of cost, revenue, coupling, and cohesion.
I found the arguments to be concise and easy to understand.
Personally, I think estimating costs and revenues is challenging, and it really tests one's skills as a technician.
In particular, I found several chapters that present ideas from a monetary economic approach to be quite interesting.