An annual increment request lands best when it arrives before budgets are set, not after. Anchor it to the date of your last review and to what has changed in your scope since then.
Yes. An unspecified request forces the other person to guess low or defer the decision. A figure gives them something concrete to take to budget.
Only if the recipient does not already have it in front of them — usually they do. The field is optional in this builder for that reason.
Ask what specifically would need to change, and by when. A documented answer turns a rejection into a plan with a review date.