何时定义GTK类，何时使用信号？

I'm fairly new to GTK, and am messing around with my first "serious" GTK (gtk+-3) app. I'd like to draw on the wisdom of others' experience about when it's suitable to define a new GTK class, or just use a "vanilla" GTK classes, and implement behaviour via signal handlers.I'm fairly new to GTK, and am messing around wi