In *general* it's fine (and a good idea because of bill lock and the bill avoidance penalty) to pay bills every day (also paying bills can trigger events, which can be good or bad). There is a tiny amount of interest on back bills.
Collections, on the other hand, are best done once every twenty days. This is because bills are based on what you *currently* have, as are taxes. (This is also why it's best to pay bills *before* buying infra, and collect taxes *after* buying infra.)
Edit: Trade set can also have an impact on ideal bill pay frequency.
Also repeat resources (I count ten -- you have a harbour so you should be able to have twelve) don't give extra bonuses -- for example having two wheat trades won't give you +16% population. (Having fish and wheat will give you +16.64% population, however).