Source here - the more frequently you pin will increase the stability and lessen the variance of testosterone levels at a given time.
If you would like to visualize it, check out websites such as SteroidPlotter.com in which you can alter the weeks, esters, etc. and see how it effects hormone levels and stability.
Now speaking practically, with a longer ester such a Test C I don't think it is a make or break case. I would still pin twice a week and call it a day.
Goodluck brother