White distilled vinegar is pretty straightforward. In recipes, it does one thing, and it does it well: it adds sourness and acidity to a dish.
Balsamic vinegar is more complicated. As wine comes in an amazing array of varieties – all with different tastes, textures and aromas – so too does balsamic vinegar. Like wine, balsamic vinegar is typically made from grape juice and aged in barrels. Unless it isn’t. That’s where it gets complicated.
Most vinegars labelled “balsamic” are simple imitations of the real thing, mimicking the most obvious flavour characteristics without the extra process (and time and cost) of a more authentic balsamic. Unless you shop at a very nice supermarket with a vinegar cabinet kept under lock and key, the balsamic found on a grocery store shelf is not traditional balsamic vinegar, or “aceto balsamico tradizionale”; instead, you’re buying what is sometimes called balsamic vinegar condiment or industrial balsamic, and the quality and taste vary widely.
If a recipe calls for half a cup of balsamic vinegar for use in a steak marinade, a relatively cheap $5 bottle of balsamic should suffice; subtle notes will be cooked out, so it’s not worth paying for something you likely won’t taste on your plate. If a recipe calls for a couple of tablespoons to be used as a finishing element, in a vinaigrette or for dipping or drizzling, a nicer (but not authentic traditional) balsamic – in the $15 - $30 range – would be a good fit. Serve it with olive oil and dip focaccia into it, or add a splash of it to finish cooked veggies.
If you’re lucky enough to have a bottle of the genuine, artisan-made article, use it very, very sparingly. Stored properly, it will keep just fine in the bottle for years, and a few drops are often enough to have the desired effect. A few drops on strawberries, say. Don’t use it in any way that would mask or draw attention away from the balsamic. If you’re paying $150 for a tiny bottle, you should be able to taste the full range of the vinegar’s flavours.
If you love balsamic, the best solution is to have two bottles in your cupboard: one inexpensive bottle for cooking purposes (marinades, etc.), and one nicer, more costly bottle for finishing dishes before serving. If you just got a raise, maybe splurge on a bottle of the real deal for special occasions. It’s the difference between having a bottle of cooking wine, a bottle of something nice for supper, and a fancy bottle of premium port for sipping with guests.