Cute concept, love a cozy idle. I think it is a little bit slow in terms of timing - waiting to be able to upgrade takes a while. To make it stronger, I would not actually directly change that timing, but add other types of upgrades than just the washers themselves. Boosts or something. You could buy like a fancy detergent that makes all the washers generate x2 money for a brief period, or hire a coffee stand that makes customers move x2 speed for a period, or even something gross like bed bugs in the neighborhood and all of a sudden customers have x3 loads when they come in. Awesome job, keep going!