What do you look for when you want to use Options?

I am interested in using options in my personal portfolio but lack any real experience with derivative products. A couple of strategies/thoughts/questions are listed below and I hope to spark some discussion in the comments. Please feel free to respond to one, all, or as many as you like. PMs are also encouraged. 

Portfolio is long-only, core built around benchmark and thematic ETFs with occasional single names I like. 

1) Portfolio Protection: I was thinking about purchasing puts on my underlying holdings so that if the price falls I can use the profits from the options to purchase more shares. Does this make sense given I only have ~$100K in the portfolio or am I just going to be burning cash on premiums waiting for the occasional position to pay off?

2) Increase portfolio exposure: With respect to the concept above, what about using calls to increase exposure and capture more of the upside, how would you look at premiums to determine whether makes more sense than using puts?

3) How do you think about Option Pricing?: When you're looking to trade options on single stocks how do you determine when the premium is acceptably priced, is it just based on how much you want to allocate/how much you're willing to risk?

4) Expiration dates for rolling options: How do you determine the best time frame to use? In the case of portfolio protection does it make sense to just roll monthly or quarterly expiration dates?