Do I need to use the subjunctive to translate whatever, however, or whether?

Grammar Genius,

Someone told me that I need to use the subjunctive to translate whatever or however. For example, how would I translate "I am going to the beach whether you come or not?"

Many of the following phrases are translated to Spanish by using the forma reduplicativa, constructions that repeat the use of the subjunctive e.g. que digan lo que digan, que guste or disguste, etc.

The second verb is sometimes omitted after a negative: estaré de tu parte, tengas razón o no ´I will be on your side, whether you are right or wrong´

´Whether...or´

Use the forma reduplicativa:

Voy a la playa que vengas o no (vengas). I am going to the beach whether you come or not.

In some cases, the second verb may be replaced by hacer:

termine su tarea mañana, o lo haga la próxima semana... Whether you finish your homework tomorrow or you do it next week...

´However much/ little´

Por mucho que/ por más que + verb, por mucho + noun + verb, por (muy) + adjective + verb. If the event referred to is or was still in the future, the subjunctive is used:

Por muy inteligente sea, siempre haga tonterías.	However intelligent he is, he always does stupid things.
Por más que se esfuerce, siempre pierde los exámenes.	However much he tries, he always failes his tests.
Por mucho frío que haga, no prenderán el calentador.	(The cold is still in the future) However hot it gets, they won´t open the window.
Por mucho que me prometa que lo haría, no lo hará.	however much he promises me that he would do it, he won´t do it.

Otherwise, if the event is or was a reality, use the indicative:

por mucho que me prometió que lo haría, no lo hizo

however much she promised me that she would do it, she didn´t

NOTE: The subjunctive may be used for actions that are realties, but only to emphasize the degree of the concession:

por mucho que me prometiera que lo haría, no lo hacía.

However much he promised me that he would do it, he didn´t.

'Whatever' or 'no matter what'

The forma reduplicative is normally used:

digan lo que digan	whatever they say
Traígalo sea como sea.	Bring it, no matter / whatever what it is like.

At times, comoquiera que + verb may be used instead of the forma reduplicativa, but it is not very common:

Traígalo comoquiera que sea.

Bring it no matter / whatever it is like.