life cycle – Two words, not lifecycle.
line numbers – Lowercase and use figures when naming word lines in individual lines of a text: line 1, line 2. But: the first line, the 10th line.
lists – Use a colon after introductory text before a bulleted list. Lists should contain parallel structure. Capitalize the first word of the bulleted content, and finish with a period only if it is a complete sentence. See lists section also.
login, logon, logoff, log in – Login, logon and logoff are all nouns. Two words create the verb form.
long term, long-term – Hyphenate as a compound modifier: They are focusing on the long term. Her unit has a long-term overseas assignment.