Brake Fluid Level Drops Slowly

[xdarkxfirex]

Is this normal? I replaced the Master Cylinder last year with a dorman, because I thought the OEM was bad from a low pedal. Didnt do much at all :( Pedal on these cars naturally feel spongy.

I also replaced the two rear wheel cylinders because of stripped threads when bleeding them. I notice my brake fluid level drops a bit like almost a cm every while. I think the reason being might be checking the level a lot and taking the basket out. I'm worried I might have a leak somewhere, but I cant find anything. I even checked the booster line and found nothing.

Is it something I should worry about? Usually when you have a leak, you have a large amount of fluid loss.