Concealer is known to hide dark spots and blemishes especially under the eyes. Foundation is used as a base before applying make up. Foundation can also correct light spots. Though there is a question about using concealer as a foundation. The answer is yes. It can be used as a full foundation and make sure to apply evenly. It is safe to use everyday if you are the type of make up on the go.
It doesn’t matter. Wearing too much make up is a turn off. A simple sunblock would do.
Most women wear make up not only to look presentable or they are used to it. Also for photoshoot purposes. 
Yeah I guess you are right that by just going out alone in the market or to buy some stuff at the grocery, a sunblock would be enough.
Good to hear that. I am not used in going out without wearing any make up. Though my face will get whiter by using a concealer. Some use concealer on top of foundation isn’t it?
Yes some women do it but mostly it is only for photoshoot or special events.