Our 25% ABV rule of thumb probably places us at the cautious end of the bell curve. We used to set the bar a bit lower at 20% and, at that level, never lost a bottle. These days we can afford to be more cautious since we have some wine fridges (Vintec) which we maintain at a constant 12°C. So those are what we mean when we say "fridge". Our cocktail bottles occupy a bit over half the space of one of them and they are about my height (195cm). The kitchen fridge, at its lower temperature, would be the best storage option but, as you say, is impractical. The bottles we've lost in the past (in our pre-cool-storage days) were all vermouths, sherries or aromatised wines. The strange, sickly smell was the giveaway...and having smelled it you will also taste it in the glass. A good bottle always smells unremarkably fresh to us. The big payoff for us in having a dedicated wine fridge is the greatly expanded range of cocktails that one can choose to make at any time.