How long does an ERC20 transaction take?

I'm curious about the timing of ERC20 transactions. Could you please elaborate on how long it typically takes for an ERC20 token transfer to be completed? I've heard that it depends on various factors like network congestion and the gas price set by the sender, but I'm still a bit fuzzy on the details. Is there a general timeframe I can expect, or does it vary significantly with each transaction? Understanding this would greatly help me in planning my cryptocurrency transactions more effectively.