If you're going to do that then you need to make sure you're logging into a different account on the phone (Google etc) than your normal one. The likes of Gmail will pull in your new sims contacts and then if you log into your social media, everything might sync and show to others (unless you're clever about the privacy settings at the start etc).
I once got caught out by some bird I'd been texting, she was able to find my social media account through an app which had access to my contacts.
Best bet is to have a separate phone with a separate account, separate contact list, the lot.