huàn zhīqián ràng shīfu gěi nǐ kàn yīxià bùyào xiū wán cái fāxiàn yánsè chà hěnduō

换之前让师傅给你看一下，不要修完才发现颜色差很多。

Before replacing, have the technician show you; don't wait until after the repair to find the color is very different.