wèn qīng shì fǒu bāo hán ān zhuāng, bǐ dōng xi sòng dào mén kǒu cái fā xiàn méi rén zhuāng gèng wěn

问清是否包含安装，比东西送到门口才发现没人装更稳。

It's more reliable to ask clearly whether installation is included than to find out no one will install it after it's delivered to the door.