The goal of withholding is to get as close to the actual amount of tax you will owe by the end of the year as possible. So ideally, you should have no refund and owe no tax when you file your tax return. If you find yourself consistently getting a large refund, that means you are consistently over-withholding.
From a rational point of view, it is disadvantageous for you to over-withhold because you are giving the government an interest-free loan until tax time. It is advantageous for you to under-withhold as much as possible, as that way the government is giving you an interest-free loan until tax time. However, if you under-withhold too much (specifically, if the withholding is below 90% of this year's tax liability and below 100% (110% for high earners) of last year's tax liability), you will trigger a penalty. So the optimal way to withhold would be to under-withhold a little bit, but not enough to have a penalty.
You would have to do some calculations to figure out how to adjust your W-4 so that you will reduce your current over-withholding to about exactly the right withholding, or maybe even a little under-withholding.
Another thing your father might be referring to is that, if you have a short-term need for money in the middle of a year, you can reduce withholding earlier in the year and increase withholding later in the year to make up for it. But you have to be careful to remember to change your W-4 again in the latter part of the year, and leave enough time for increased withholding to make up for the difference (W-4 changes might not take effect immediately).