Identify what vinegar is doing in your recipe: leavening/acid in baking, tang in sauces, or acid strength in pickling.
Start with a 1:1 swap ratio for most non-bread recipes (dressings, marinades, cooking).
If the substitute is sweeter or milder (champagne, rice, lemon), use 1.1x and taste; if it’s sharper (some malt/cider), use 0.9x.
For quick pickles, make sure you’re using unseasoned vinegar (or plain lemon mix) and taste after 10–15 minutes of chilling.
Taste again at the end—vinegar flavor shows up quickly, so small adjustments are safer than big changes.