The phrase "needed and necessary" is correct and usable in written English.
You can use it to emphasize that something is both necessary and wanted. For example: "This new piece of legislation is both needed and necessary in order to achieve our desired goals."
To me that would be a needed and necessary reform.
It is well known that for any ill-posed problems an a priori bound assumption for the exact solution is needed and necessary.
If urban water management is to be a central foundation for a sustainable future for Sydney, reforms are needed and necessary.
"But it's unquestionably needed and necessary".
Simple dialogues such as this are desperately needed and necessary for a peaceful, prosperous future.
They both agreed that educating youth to be safe and productive online was needed and necessary in the school system.
EU leaders said measures to restore confidence in the bloc's banks "are urgently needed and are necessary in the context of strengthening prudential control of the EU banking sector".
Also, many undergraduate institutions are already well positioned to pursue projects in synthetic biology because only basic computer and molecular biology resources are needed and the necessary reagents are relatively inexpensive.
Such strategies may include purchasing of green cleaning products, identification of the areas where disinfection is needed, and following the necessary disinfection procedures in the cases when disinfection is necessary.
Further investigations are needed and it is necessary to study the recurrence rate from this aspect, including the rapid reduction of serum albumin and the proportion of oxidant human serum albumin in patients after RFA treatment.
To obtain the needed concentration and necessary amount of DNA from all individuals, DNA isolation was performed in triplicate.
