• indicates the person who receives something: This course is for you.
• indicates purpose or reason: Thanks for the birthday card.
• indicates a destination or distance:  We walked for miles
• indicates periods of time: I’ve know him for about 6 years. Do this exercise for 10 minutes.

Phrases
for ages = for a long time I’ve known her for ages
for now/ for the time being – For the time being concentrate on this course. Don’t worry about getting it right for now.
“What for?” = why?
be all for something / up for = approve of: I’m all for having some fun. I’m up for having a drink later.
If it weren’t for/ if it hadn’t been for – If it hadn’t been for Lisa, I would never have got the job.
for all I/we/you know – it may be true but it’s not important –  For all I know, he may be a hundred.

for all = despite – For all their faults, it’s a good company to work for. 

but for…, as for…, for one thing…, for a start…