Your aloe will literally shout for help in plant language. If the leaves are super thin, pale, or flopping over the edge of the pot like a tired cat, it’s time. Another clue: roots poking out the bottom of the pot like they’re trying to escape.
And if you water your aloe and the water just sits on top for ten seconds? That’s a red flag. The soil has turned to concrete, and the roots are suffocating. Your plant is basically breathing through a straw.