When I use thread to stitch something to my bag I usually loop the needle through the fabric three to four times before tying it off.  That helps make it extra secure! 

Then if you ever want to take it off later you can use scissors to remove it (or nail clippers if you don’t have them).

I also prefer not to use ball chain connectors on any pc holders or keychains, I find they fall off easily.  Whenever I can replace it with a lobster clasp or sturdier connector I do.

Some people say they prefer having a smaller concert bag since it’s easy to carry.  So it’s completely up to you what style you use!  I like to bring a more in my bag so I always go with a bigger one when I can.