Changed password applies across devices?

Stupid question maybe but experience makes me nervous.

(Background before getting to question. I wanted to add an app Word for I-pad, only way I can write and print anything at moment. So needed Microsoft password. This I understand would be same thing as my Outlook e-mail PW OK? My devices remember this so I don't need to, but I thought I did. To my surprise it was not recognised. I thought I'd better reset it - but that was hassle. Because I can't get into my security thing without password! There is a simple procedure but it required the telephone number of a phone I no longer have and don't remember! I found an alternative method which requires supplying lots of information so they can identify me, and requires another e-mail - and can take 24h! So I'd rather not do that again!).

I've changed the (hotmail e-mail) password on one device - netbook computer. E-mail on other device - I-pad still working. Say I switch I-pad off - will it still remember/use my new password next time I switch it on? Or will I have to go through same trouble on that again, wiith a period of loss of service?

While at it, related question on e-mail. I have mostly in-tray open. If I look at other boxes, Sent and others I have created it shows only very most recent messages, often none at all. On the netbook or computer II see them all. They are still there if I search on the iPad version. I guess this is normal?