I make my own too and I make a lot at once and then put it in the fridge for 3-4 days then transfer all but one jar to the freezer. The Prep Time and Servings depends on the amount of Horseradish you have and want to make. I highly recommend you make this outdoors or in a well ventilated area.
Here's my recipe if you want it:
Ingredients
horseradish root, as desired
white vinegar, as required
salt, as required
Directions
Cut roots into manageable pieces.
Scrape the outside of the horseradish roots until clean.
Drop into cold water after scaping to prevent discoloration.
Drain and grind up fine with a handgrinder, food processor or in a blender with a little vinegar.
Spoon into clean jars, filling to about 2/3 or a little more full.
Add 1 tsp of salt to each jar, then fill with white vinegar.
Cover and refrigerate for a few days before using.
Hope that helps ya a bit.