Squeezing spokes and calling it good is like checking if a cake is done by poking it with your finger and hoping for the best. Imagine paying full price for a wheel and the guy's "tension check" is just a firm handshake. Bet that wheel starts making noise on the first bump and he acts like it's a mystery.

Been down this rabbit hole myself after reading a thread on a plant forum about how most bagged mixes are cut with way too much peat and not enough chunky stuff. Someone did a side by side with plain bark, perlite and a little charcoal and the roots looked totally different after a few months. For a balcony though you don't need to go full docent mode, just grab a bag of orchid bark and mix it into what you already have. Even a small change like that can help with air flow and stop the mix from staying soggy. Worth a shot if your plants seem slow or the soil feels heavy when you water.