Do I want a stranger helping me?

Sorry for the clickbait but I need some help.

I am a SAHM with an 18 month old and another on the way. We have some room in our finances to hire someone and I don’t know what I want or what is best.

Advice?

Nanny part time? Like two full days a week? What will they be able to do for me? What do they do when my kiddo takes a two hour nap break? Do I need to feed my nanny? Do they clean? Are nannies focused more on education?

Should I get a babysitter for three nights or mornings a week? Probably 4 hours per day. Are mornings preferred? Like 8a-12p? Or afternoons? 3-7p? Why?

Anyone with experience either way would be awesome. Thank you so much!!