Yes you will come to know about it depending on your end results as if you win then it was your day and if not then you can consider it as an unlucky day for you and in gambling there will be very few instances when you will feel that it was an lucky day for you.
That is worthless hahaha !
If you aren't able to know if it's your lucky day before you start playing, you aren't preventing yourself to lose money. The risk here is very high, you can lose lots of money just by trying to know if it's your lucky day or not and in the end, you will see your lucky day isn't enough to recover all the losses you had on the another days you wasted money trying to know if they were your lucky days or not.
LOL. yeah if anyone is able to know an exact time when he'll be lucky, then that person would've been rich already gambling only on the days he'll be in luck. Simply put, you can't really predict when you'll.be lucky or not. It may or may not come at all on a single day. All you can do is to make the most of the aspects that you have control of like managing your money wisely.
Checking today is your lucky day or not with your money in gambling is actually worthless and time waste. Because no one can predict what will happen tomorrow especially in gambling you can not guess whether you will win your bet or not 100% correct result. So don't waste your money to check your luck. Believe on your skills and play only known games and choose only low odds to bet then you may find out your lucky day.