Hi guys, im in the process of keeping my hair long. Right now its only around 4 inch. So ive read a few articles and some suggest to use hair serum and hair oil.

Just asking for opinion here so that i dont get the usage wrong.
If i take bath once in the morning and once at night. The best usage scenario would be to use the hair serum after bathing with conditioner in the morning right? Because serum works as hair styling so i guess it replace things such as hair gel?

While hair oil is best use after taking bath at night to restore nutrition to hair. Can we go to sleep while having the oil? Would it like damage the hair having the oil during our 8 hour sleep?