I never used a thimble when I did counted cross stitch, but a friend insisted I use one - that was 30+ years ago and now I just can't sew anything without one. My one vanity is acrylic nails with gel polish so I have to make sure I get one that fits. When I applique or blanket stitch, I use a silicon one my left hand index finger. When I quilt, I use Marian's Magic Quilting Thimble
http://www.momsmagicthimble.com/.