Hello mates! One does really need a 5 ? I am interested about it but since I am intermediate player I dont want to slow down my learning or even complicate my already gained progress, but maybe the 5th also teaches me new things , like expand the scales and stuff...
Its easy to say " go get one" , just keep in mind that I dont have a big budget to own 2 basses so I would have to sell mine 4 string to get a 5.
You're talking to a guy who, back in the Pleistocene, after hearing Heavy Weather, went to the shop and had them remove the frets from his ONLY electric bass, a Fender Jazz Bass, and who picked it up an hour before his next concert. After that, nothing seemed like an extreme experiment again
It's quite personal, conditioned by possible business considerations. If you're playing in bands or learning tunes at home, not getting any complaints, and not missing those low notes, of course you don't NEED a 5 string bass. Be happy with what you have. If you want those low notes for reasons of curiosity, personal taste, or business, consider a 5 string instrument. You can always go back to 4 strings if you don't like it. If you're playing shows the parts may actually have the low notes written in, and you'll either have to have a 5 (or a 6) or make an octave adjustment, which can be OK...or not.
Strictly from my POV, I would never discourage experimentation; I went with 6 strings in the 1980s after hearing Anthony Jackson's work, and never really looked back. It took a while to get used to the additional strings - the hardest thing is that you lose your memorized physical landmarks, i.e. the pitches of your open top and bottom strings, their pitches at the octave, etc.. But it was worth it for me to be able to get those low notes clearly and to be able to finger passages more across the fingerboard rather than shifting constantly as with my string bass.
On the other hand, I've just been playing around with a 4 string Jazz Bass copy and loving it; it lets me play more like I'm playing my 4 string upright. You can play great bass with 4, 5, or 6 strings, it's really up to you. (Hey, a few hundred years ago basses had 3 strings!)