@WW Thanks - I found this topic difficult to google. It does seem that we can sometimes drop "for" with time-duration expressions where the meaning is clear from the word-order.

Re "however": this no longer appears in the latest Strunk and Cowan online. Indeed it includes:
"However, the distinction is often fine and sometimes invisible."

For IELTS purposes, instead of "however", I usually tell my students to think about using "although" or "whereas" , and joining up with the foregoing sentence. (The marking criteria include: "uses a variety of complex structures".)

To me, there are two special things about "however" vis-a-vis other adverbs such as "admittedly" or "nevertheless":
1) "however" tends to mark the foregoing word as the item of contrast.
2) "however" is more readily mobile in terms of position.
Consider:
a) However, he was very young.
b) He was, however, very young.
c) He, however, was very young.
d) He was very young, however.

I teach people to use commas here off because the examiner may have been raised on Strunk, and I sometimes question the use of "however" at the beginning of a paragraph, as it so often betokens lack of topic cohesion withing each paragraph.

More grist:
1) "He searched five years for his estranged daughter."
2) "He sought five years his estranged daughter."
3) "I was two years buiding a trimaran."
4) "Seven years I studied Latin."
5) "i was two hours waiting for the ambulance"

The important thing to grasp is that punctuation converts to form part of an audio file in your head: listen to the voice in your head as you read this. So the question becomes:
how does one pronounce a comma?
Usually as a small pause with a rising or wavy intonation.

Most text layout affects how the text sounds in your head: consider
poetry and
the effect
of an end-of-line
on intonation
and rhythm.

It is worth noting that graphics such as bar graphs, and pie charts do not produce an audio file in your head; but columns of figures on a spreadsheet or accounting report are usually "read" as audio input.

My understanding is that in the Middle Ages, European people generally read everything aloud; punctuation was introduced to help them do that and we have kept it because we read "aloud" in our head. Not every language is like this - Thai leaves no spaces between the words; older Arabic has no punctuation.

When writing in modern English, the whole layout, including whitespace between words, whitespace between paragraphs, whitespace indentations, and also punctuation in general - this all is used to help the reader. Recent research has shown that a European reader focuses on just a few letters at a time - something like the last letter of the previous word and then the next eight or so letters - apparently this is all the retina can take in at one time. The eye then jumps to the next group of letters. It is this scanning process that limits reading speed, not the conversion from letter symbols to meaning.

Conventionally, a colon marks a longish pause with a flat, wavy, or slightly rising intonation; but definitely without the falling intonation associated with the end of a sentence. If that is how you would say it, then a colon may be the right way to go - there is no particular rule as to how often.

For example: "Roses are red: violets are bluish, and come in three colors: dark blue, violet and indigo."
Note that here we have used a colon in two different situations: between two independent clauses; and to introduce a list.

"-age" is a "suffix typically forming mass or abstract nouns from various parts of speech, occurring originally in loanwords from French (voyage; courage) and productive in English with the meanings “aggregate” (coinage; peerage; trackage), “process” (coverage; breakage), “the outcome of” as either “the fact of” or “the physical effect or remains of” (seepage; wreckage; spoilage), “place of living or business” (parsonage; brokerage), “social standing or relationship” (bondage; marriage; patronage), and “quantity, measure, or charge” (footage; shortage; tonnage; towage). "

Thus words like leverage using the suffix "-age" are prima facie expected to be nouns, and one would normally use the root as the verb as in "to broker", "to break". That said, "leverage" seems to have developed as special meaning of its own, distinct from "lever", so it becomes meaningful to use "leverage" as a verb.

In some ways this is similar to "influence" which one would expect to be a noun like other words ending in "-ence" or "-ance"; however we did not bring in the root verb "influe" into English so we use "influence" as a verb too.

http://books.google.com/ngrams/graph?content=in+the+long+term%2C+in+the+long+run&case_insensitive=on&year_start=1800&year_end=2008&corpus=15&smoothing=3&share=&direct_url=t4%3B%2Cin%20the%20long%20term%3B%2Cc0%3B%2Cs0%3B%3Bin%20the%20long%20term%3B%2Cc0%3B%3BIn%20the%20long%20term%3B%2Cc0%3B.t4%3B%2Cin%20the%20long%20run%3B%2Cc0%3B%2Cs0%3B%3Bin%20the%20long%20run%3B%2Cc0%3B%3BIn%20the%20long%20run%3B%2Cc0

I dont see why we need apostrophes at all: after all we manage to understand speech without them - and somehow get by without making making an explicit distinction between genitive singular and plural. "Besides" is historically a genitive form, but we dont mark it with an apostrophe in modern usage. Why do we need apostrophes at all?

Punctuation is very much a convention of signals which guide the reader as to how the sentence is to be read and construed. One might consider a comma as a one-beat pause, a semi-colon as two, a colon as three, and a full-stop four; but they also hint at the intonation in the same way as a question mark does.

Whilst punctuation is just a convention, there is nothing per se to stop one from using both a colon and a semi-colon in the same sentence, if that is what is truly necessary in order to guide the reader along.

In your example sentence, however, I would question the use of a semi-colon to join the two main clauses together. To my mind, one should be able to substitute "and" , but this does not work for me. For example: "Roses are red; violets are blue." Here, one can substitute "and"; the sentences have parallel structures, which helps.

Did you mean something like:

Colleges provide help for students who are struggling. They offer guidance with study skills to keep on top of coursework and homework, advice from counselors on dealing with the workload, and the option of dropping a class early.

Just to make it clear: when reading slowly many people are actually "reading aloud in their head"; (if not, then one is technically "skimming"); either way if one cannot read a text out loud correctly first time, then it is not clear; and commas may be needed to make it so. Thus:

"In general media, people today often seem to omit commas wherever possible." is not the same as:
"In general, media people today often seem to omit commas wherever possible."

In short, put commas where needed to make the meaning clear first time so the reader does not have to backtrack and reconstrue the sentence. Elsewhere, commas are functionally redundant.

Where is "here"?