I don't really get it? How do you want to spend your bitcoins if you already have most vital asset in your possession? Well if you already have 4K dollar bitcoins then that is you investment itself. Consider the fact that bitcoin is volatile and it's up trend is exponential over spacious timeline, you can easily turn your 4K worth bitcoins into cool fortune.

If you are thinking of exchanging the bitcoin to altcoins then that would be really bad idea. You will exchange the coins for less secure and less profitable coins and thus may end up turning your 4K upside down.

Do not go for gambling, that's most stupidest idea if you do not have self control and limits on gambling. 

Just HODL!