It would be cool actually: red for Pascha, white for Ascension, green for Pentecost and Palm Sunday, black or purple for Lent, blue for Feasts of the Theotokos, gold most of the year. It would be doable if you had 6 sets of toothbrushes.
Well, actually I wasn't being serious, lol.
It would work out ideally if there was a change every 2-3 months. Just get a new toothbrush in a new color, and it would remind you to change it.
I suppose if you wanted to just match your toothbrush to the liturgical season, you could just develop colored toothbrush sleeves, and could change those out.
But why stop at that? I'm sure you could decorate all toiletries according to liturgical season - shampoo bottles, color of soap, color of razor, and bath towel too, for that matter. (Since this is a "Hyperdox" thread?)
Perhaps curtains in the home, bed linens ...