is it necessary to apply moisturizer?

agree with zoozoo, moisturiser is to hydrate and lock the hydration from the products before moisturiser. you can find lightweight moisturiser and non comedogenic ones. I personally enjoy these moisturiser as they are lightweight. I notice you have oily and sensitive skin, just like me, so these would be great :) I use TIA’M in the morning as it keeps my face from becoming oily throughout the day. I use Iunik and I’m From at night. Sometimes I skip moisturiser and go straight to sunscreen because some sunscreen is hydrating enough. So, it really depends on what your skin prefers. You shouldn’t worry about the clogging because that is why you cleanse your face twice a day. Double cleanse if you have make up on or sunscreen. I only double cleanse if I have matte sunscreen on. Other than that, I double cleanse only every two days to just clear the gunk and clogged pores. :)

you could used non comedogenic moisturizer,sometimes I didn’t used moisturizer or skip moisturizer because i feel my face is well hydrated,but moisturizer function is to hydrate and lock hydration on your face to prevent it evaporated,moist is the part of basic skincare but if u feel enough with your skincare rightnow,i think its fine to not used moisturizer,maybe if you want to try moist try lightweight and gel type 😊

in the morning, if your sunscreen moisturising enough, then you can skip moisturiser. and some essences are also moisturizing. During the night, I think you may use a gel moisturiser since you have oily skin like me. but I will add anothee thick cream to keep my skin moisturized because I sleep in an aircond room so my skin may get dry if I don't seal the moisture.

in theory, yes, adding more products can clog your pores. but it takes a lot of products to clog your pores, unless that product is comedogenic. like zoozoo said, look for a moisturizer that’s non-comedogenic. the main function of a moisturizer is to lock in the hydration within our skin and reduce trans-epidermal water loss. if you live somewhere cold and dry, i’d say moisturizer is necessary. if you live somewhere hot and humid, you can skip the moisturizer as long as your skin is well hydrated and moisturized, and instead use an emulsion since it is lighter

You don't have to if you feel your skin already get enough moisture. But moisturizer help skin to prevent water-loss and dryness. Still it depends on your skin