This however doesn't grant you days off - if you don't work you don't get paid.
Also, at least in Germany, if you only have one client/customer, you're vulnerable to committing a tax/social security offence called "Scheinselbstständigkeit" (roughly: faked entrepneurship), as you'll end up paying less in taxes, social security and insurance than a full-blown employee and people have abused this in the past to maximize their profits on cost of the employee or the systems.
Sure, this is the 'contractor' approach where you bill for services provided at a higher rate than a pure salary, and pay for your vacations/sicknesses/whatever out of that.
As for that "Scheinselbstständigkeit", I believe most other countries have some similar legislation. It's not an issue with freelancers as you have rotating clients, even if it's only one at a time; but yes, if you're creating it just for a single employment then that can be treated as tax avoidance - having the employer run a shell-subsidiary-branch would be preferred in that case.
Also, at least in Germany, if you only have one client/customer, you're vulnerable to committing a tax/social security offence called "Scheinselbstständigkeit" (roughly: faked entrepneurship), as you'll end up paying less in taxes, social security and insurance than a full-blown employee and people have abused this in the past to maximize their profits on cost of the employee or the systems.