There is only one way to find out, as I recently did for my own curiosity. Reading what others think, either for or against, about the need for "better" cables is useless. You need to make that determination yourself. Follow what I did and you will have your answer. Contact a retailer that will allow for a return within 60 days. All it will cost you is the return shipping to make your own determination. It would have cost me all of $28 + insurance to find out for myself that YES, speaker cables and interconnects do make a difference. So I kept them. I contacted a popular online retailer and asked them to ship a full set of the most recent Shunyata Venom-X cables. The first cables I swapped out were the speaker cables. I was pleasantly surprised at what I heard. I listened to a total of 10 albums between SACD and vinyl. Then I would replace another cable in my system and again listen to the same 10 albums. By the time I replaced all cables and listened to the same 10 album each time my system was truly "singing" to me. For years I have been skeptical. Now I am not. They do sound different and in my case they sound significantly better than what I was using. Total cost was in the neighborhood of $4,300. Not a lot different, if at all, than adding a new device to the system to enhance the sound. I am happy I did this little experiment.
edit: Don’t shy away from buying "open box" cables as they will be much less expensive. I did that with the Shunyata speaker cables and saved $700.