zuì hǎo wèn qīng chǔ shì lǐ miàn dǎ báo fà wěi dǎ báo hái shì zhěng tǐ dǎ báo

最好问清楚是里面打薄、发尾打薄，还是整体打薄。

It's best to ask clearly whether it's thinning the inside, thinning the ends, or overall thinning.