"close and constant" is correct and usable in written English.
You can use it to describe two people or entities that are in together in a close, continuous relationship. For example, "Their relationship was close and constant; they had been friends since they were children and always kept in touch."
"We keep our travel advice under close and constant review.
He's not in close and constant contact with the candidate".
And that requires close and constant collaboration between marketing and IT.
Mr. Baynham's seat is next to Mr. Winer's, and their collaboration is close and constant.
"And that's a good thing in a state whose natural resources are under close and constant scrutiny".
Kerry said: "Our embassies in the Philippines and Palau are in close and constant contact with their partners in local governments to direct aid to the right places.
A few wondered if anything could be done about the increasingly sorry state of the business, about developers like Irrational and 38 Studios closing and constant downsizing, but not many questioned how it had all happened this time.
Our to-do lists get longer, our deadlines loom closer, and constant access to digital devices means few idle moments.
With Hurricane Isaac looming ever closer and constant local distractions like strip clubs and wildlife, the correspondents had trouble focusing on the issues.
From Basra, the brother of San Diego resident Najem Al Ekabi, 51, described a town under siege, with water and electricity cut off, schools and shops closed and constant explosions from missiles and artillery.
He said the paper's close presence and "constant tracking of activities using text, pictures and video" have played an important part in keeping the project moving forward.
