I suppose the pros are being supported? Otherwise I don't know what the point is. Maybe learn or grow from them. Cons, dealing with the highs and lows I assume.
I actually haven't had a partner before though

Pro: less lonely times, con: compromises and a real chance to become lonely again.

Pro's is you have company, someone there to cheer you up and look after you when things go bad... sex is nice too. Cons... they take a lot of financial, time and energy commitments, then theres expectations to meet, limiting sexual and romantic possibilities (if partner is monogamous), having to deal with their family.

Cons: slightly less freedom, you'll have to hear their rants, you have to make them feel good, if living together the food consumption and housework need will be higher, you will hear farts/burps occasionally, probably many more depending on which partner you choose.

Pros: you become part of a cute couple, they make you feel good, if living together you'll have shared costs and housework, they'll hear your rants.

There someone who will have your back, who you can rely on when times are tough, someone who will support your dreams or passions , someone to bring you a Dr Pepper when you do not feel like getting up 😛

There aren't cons if you are doing it right

Pros: you’re not alone, someone always has your back, built in best friend, fun sleepovers. Cons: making compromises, less flexibility (to do what you want when you want it)