Are there mechanisms that limit the amounts of time conjugation and F-plasmid transfer can happen? If yes, what are they?
Yes there are many such mechanisms.

One of the simplest, but perhaps most easily overlooked, is metabolism.  Conjugation requires ATP.  In environments with low levels of nutrients, heterotrophs might not have enough "extra" ATP to fuel the conjugation process.  Note that both donor and recipient need to expend ATP in conjugation.  The donor needs to make the nicking enzyme, the pilus, and extrude the DNA into the recipient, and the recipient needs to synthesize DNA from the single-strand DNA that it has received.