How did you approach sponsorship ads in the early days (and now as you've scaled)?

Hi everyone. Have a [small] side startup that is launching a new project (newsletter). I have some connections from it that I think can give us our initial sponsors.

Curious how you would approach it? Give them 'post/ad' for short term (3-6 months or X clicks/newsletters - whichever comes first) or just lock them in for the year?

I'd love to hear how approached it.

Especially as your newsletter grew and you'd have [assuming] higher chances at bigger sponsorship ad sells?

Any feedback is appreciated!

Ps: it'll be a (somewhat) daily newsletter (3-5/week)