It depends on the length of your hair, but it should last a good while.
Yes, you can bring a big bottle of shampoo in your checked luggage as long as it complies with the airline's regulations on liquids.
If you open the bottle, you need to keep it refrigerated and it will last for a month. If it is an unopened bottle it should last for about a year :)
Yes, you can bring a bottle of shampoo in your checked luggage as long as it complies with the airline's regulations on liquids and is properly packed to prevent leaks.
It will last as long as the bottle holds up.
It should last indefinitely if kept in a cool dark place.
A bottle of sparkling wine should last for years if properly stored on its side in a cool dark place with proper humidity.
If you wear foundation out of that bottle every day, and you don't wear a ton of it, a 30ml bottle of foundation should last you two months.
till the next shampoo
It should last indefinitely if stored in a cool dark place.
It should last indefinitely if kept in a cool, dark place.
The instructions on the label on the bottle or box should give you a good indication. For an answer more specific to you, you should consult a medical professional. After all, there are two possible meanings to your question - how long does a dose last, and how long does the bottle last. But both answers could be derived from the label. (Note: It the bottle lasts longer if there are no artificially created reasons for needing to use it more, such as the ingestion of delta-9 tetrahydrocannabinol.)