Here is my opinion on how many email accounts someone should have on average
Everyone who owns a chromebook or android tablet android phone, or android tv box, needs a G-mail account, you need it for the services but not many people give out this email.
Everyone who owns a Windows PC, has a hotmail address, a xbox account or who has office 365 subscription or purchases windows apps from the microsoft store, or has a work email or school/college/university email usually has a microsoft account. people who've been using the internet for many years might have a hotmail account because when email accounts were being made available, back in the day, hotmail was one of the first so a lot of old timers have one.
People may also want another email account which is not tied to their main email for the purposes of job hunting, job recruiting, or having a small business, or for coupons and mailing list or just for disposable email purposes often went with a Yahoo account. Yahoo is also more than just an email account they have stocks, finances, chat, etc so you can use the same account across their different products.
I am the second option, I have had a hotmail since the 90's i use it as my main e-mail, I have a gmail address but dont give it out nor do i use it but it came with the account so be it.
I also have a yahoo account so when i was job hunting when younger it was a professional looking address with my first name and last name so it appeared professional, unlike my hotmail which is an alias which relates to hobbies and interests of mine.
I used to have a ISP email account back in the day too, from rogers and bell but I learnt a valuable lesson because i used to use that for job applications but when i changed internet companies i lost out on a job opportunity cus my email cancelled when i changed internet companies and i didn't get the job.
so my bet is go with hotmail or gmail as your first priority, even if ur computer illiterate, there is simple ways or tutorials teaching you how to import your address book, but trust me, some people dont even know what an address book is to begin with.