There are programmers who can easily replace 3-4 and even more average programmers. How they structure their time is not your concern. As an employer you should

There are programmers who can easily replace 3-4 and even more average programmers. How they structure their time is not your concern. As an employer you should have reasonable expectations in regards to what you should get from particular employee / contractor and if those expectations are met then the rest is not your business. If they're not met then the employee should be shown virtual door out. If however the employer can not see whether they get what they pay for without employee sitting in the office then said employer has bigger problems. And these employers will be scammed / fallen victims of their management incompetence anyways disregarding of in office / out of office style. Myself, I am both Employer and subcontractor since 2000. There was not a single time for me when I was in doubt as an employer whether I am getting my money worth. And as subcontractor I value my reputation and more then happy to present whoever hires me with stellar real references. As a subcontractor I normally develop rather large pieces upon which we agree upfront and there is rarely need for me to report daily details / progress. 2 weeks to 1 month cycles are more normal.