Is old mascara bad

It depends how old it is, you can tell if it's old when it a little less liquid as it was before, or if it has more clumps. It really isn't good to keep wearing mascara that is old or has those tendencies because it can cause damage to your eyelashes (it will cause them to fall out). I suggest you purchase a new mascara every 5 months and don't forget to keep cleaning the mascara wand this will help with any clumping even if it is fairly new, it'll also prevent bacteria. Hope this helps :D