should
v.v. to say that something is a good idea or the right thing to do. You use it to give advice or talk about what you expect to happen.
v. to indicate obligation, duty, or correctness, typically when giving advice or instructions. Functions as a modal auxiliary verb and precedes the base form of the main verb.
You should eat more vegetables for your health.
If you want to arrive at the airport on time, you should leave the house at least three hours early.
The committee suggested that the department should implement more rigorous safety protocols to prevent future accidents, though the final decision rests with the board of directors.
From Middle English scholde, from Old English sċolde, first and third person preterite form of sċulan (“should,” “have to,” “to owe”), the ancestor of English shall. By surface analysis, shall + -ed. Cognate with German sollte, Gothic 𐍃𐌺𐌿𐌻𐌳𐌰 (skulda), Swedish skulle. Related to Middle English shild and shildy. The loss of /l/ in this word is probably due to weak stress, as in would and could (though in the latter, the /l/ was due to the analogy of the former two).
Modal verb — does not take 'to' before the following verb and does not change form for different subjects.
You should to goYou should goModal verbs like 'should' are followed by the bare infinitive without 'to'.