When speaking in Spanish, are pronouns frequently dropped or just occasionally and does it matter which person is being used?
For example: I often hear “¿Como estas?” or “¿Como esta usted?” but I don’t think that I’ve ever heard “¿Como estas tú?” Is it common to drop a familiar but not a formal pronoun or am I just not hearing the right conversations?
I don’t mean to limit this to “How are you?” kind of questions even though that’s what my example uses.
In Spanish you (mostly) don’t use pronouns if you don’t need them, except when you want to make a point by saying the unnecessary pronoun, for whatever reason. Taking your example, the verb estar, present tense:
Yo estoy
Tú estás
Él/Ella/Usted está
Nosotros estamos
Vosotros estáis
Ellos/Ustedes están
So ¿Cómo estás? is clear, and as using tú is rather informal, you can and mostly do omit it. It is clearly second person, singular.
¿Cómo está? could refer to him, her or the person (Usted) you treat deferentially. So you say it, to be clear and to express the respect this person deserves.
¿Cómo están? is clearly them (tercera persona), plural. You don’t need to say it, but you can. ¿Cómo están ustedes? is perfectly correct and normal, but second person (plural you), it changes the phrase slightly, making it more inclusive and respectful. No big deal.
¿Cómo estás tú? can be used, it is slightly redundant, but I can imagine the following conversation, perhaps after a mishap ot an accident:
¿Cómo están todos? (See? Them, not you, ustedes)
Bien gracias, ha sido un susto.
¿Y cómo estás tú?
Bien, bien, no ha sido nada.
So first you ask about all people concerned, then you insist on your interlocutor specifically.
Now you need to improve your accent placement, if you allow me to comment that. (And don’t tell me what I need to improve in English, please, it is hard enough as it is! 
)
Thanks for the detailed and informative answer.
I wondered about the accent in “está” but it’s been 40 years since my high school Spanish class and I was too lazy to look it up.
And como/cómo. Como: I eat or like, like in “this is like that”. Cómo: how. Seems subtle, but it is perfectly logical if you understand the rules.
I understand why como doesn’t have one but not why cómo does. What’s the rule? I’m 99.999% certain that the pronunciation is the same. Is qué subject to the same rule?
So you can distinguish them in writing:
¿Como? → Do I eat? (stupid question, I know, but that is what is written there.)
¿Cómo? → How?
And it may be my imagination or me overpronouncing it as a pedant that I sometimes am, but there is a slight difference between both comos. The one with the accent is more pronounced. Ever so slightly.
Better example:
¿Cómo mañana? → Like tomorrow? How tomorrow?
¿Como mañana? → Will I eat tomorrow?
This is called pro-dropping. Many Romance Languages like Spanish get it from Latin.
There are some rules, though:
https://www.rae.es/dpd/pronombres%20personales%20tónicos
El español es una lengua de sujeto no obligatorio (Vino y nos dijo que no saliéramos a la calle). Esto no significa, sin embargo, que la aparición o elisión del pronombre de sujeto sea aleatoria o indiferente. Por el contrario, es fácil reparar en que la aparición de sujetos pronominales explícitos es a veces anómala, mientras que, en otros casos, su presencia es posible o resulta imprescindible.
If my Spanish was that good, I wouldn’t be asking the question.
It says that when él, ella, ellos, ellas function as subjects, they can only refer to persons, not things. E.g., He leído tus últimos informes. Enhorabuena: son claros y ofrecen numerosos datos (no “ellos”)
Subject pronouns can be made explicit for contrastive purposes or when the subject is the focus of the sentence. E.g., Yo creo que en eso estuvo mal. Also to undo ambiguities [e.g, Mal podía ella preconizar una huelga de hambre teniendo el estómago lleno], and often to make explicit the sex of the referent. [e.g., Un futuro esperanzado requiere cultivar el acuerdo, la reciprocidad, también entre nosotras y ellos] “Usted” very frequently is used to reinforce politeness or undo ambiguity with a third person: Debe usted partir a París en seguida
Yes. Como and similar words que, donde, cuando, cuanto, etc. are written with accents when referring to identity… or something like that. The rules are intricate and not easily memorized, but the concept is simple enough to get your head round it. Usually happens in questions, but also sometimes in other kinds of sentences. Some examples:
¿Dónde estás?=Where are you? Typical case of accenting a “question word.” Similarly, the three example questions in your first post in this thread should start with cómo.
Me pregunto dónde vive.=I wonder where she lives. Without the accent, it would mean “I wonder in the place where she lives,” as in someone wondering about something while they are in her house.
Yeah, it’s not a good example. Not likely to come up in real life, and, even if it does, nobody is going to be thrown by the missing accent. A better example would show that the accent is sometimes necessary to avoid ambiguity.
Como como como, ¿cómo voy a comer como no sea como como?
I eat the way I eat, how could I eat any other way?
Now mess with the accents and you won’t get fed at all, no matter which way you eat.
Eeeer… no. But never mind.
What? You can’t even provide a coherent example. 
That is a perfectly cromulent Spanish sentence. Do you want me to explain it step by step?
Even internet translators get it mostly right.
This is largely true in Hebrew too. Verbs are heavily inflected, including baked-in information about the person (1st, 2nd, or 3rd), number (singular or plural) and gender of the subject. Where the subject is not specifically named (that is, where the subject would just be a pronoun), that pronoun is usually redundant and usually omitted.
Exception: Present tense verbs. The above applies to all the other tenses and constructions of verbs, but verbs in the present tense are much simplified: They only have information about gender and number but not person. So pronouns are not redundant there.
It is misleading to think of Hebrew verbs as having a “present tense” like an Indo-European language. There are only a perfect tense and an imperfect tense. You are thinking of the participle, which expresses simple duration (as opposed to repeated or progressive actions which are expressed using the imperfect tense).
It is not true that the participle always has to have a pronoun when the subject is not explicitly named: e.g. Habakkuk 2:15
But I am just nit-picking, as you are correct that Hebrew is at least to some extent a null-subject language.
Well, to be sure, I was keeping it simple. Hebrew verbs have many different binyan, or structures, which are organized very differently from verbs in languages like Spanish.