Writing Pet Peeves - "Use to" And "Suppose to"

This is another one seen frequently on social network sites.  Again, it is a case of people writing the way they speak, and words are not often spelled the way they are said.  Enunciation tends to be a problem, but that is a small part of how some words are commonly misspelled.

"Supposed to" - commonly misspelled "suppose to"

This one is tricky because it is an idiom.  People mistakenly misspeak and misspell this one because the correct usage and the incorrect usage sound so much alike and many who say it and attempt to write it have not often read it in context.

The idiom refers to a supposition that has been made (hence the past tense) about someone or something.

Meanings: 
Intended to -  This gift was supposed to (intended to) be for John.
Believed to - He is supposed to (believed to) be out of town.  What is he doing here?
Expected to - You are supposed to (expected to) be home by midnight.
Required to -  I'm supposed to (required to) call home to check in by eleven o'clock.

Not supposed to: not permitted - You're not supposed (not permitted) to be in there.

"Used to" is prone to same common misuse as "supposed to."  (Use to.)

This phrase is also an idiom, and is used in the past tense.

Meanings:
Accustomed to or habituated to - I'm not used to (accustomed to, habituated to) this cold weather
Formerly - That used to be (was formerly) a nice hotel before it fell into disrepair.

We are supposed to use grammar correctly in writing and speaking.  Although we used to write and spell these two idoms correctly in days gone by, social networking, texting and tweeting has all but put an end to their correct usage.  More's the pity.