I like to think it's not wasting my time if I do it once a day or once a week when I wait something else to finish. I get most of my coins from trading, so small amount of coins that I get from faucets are like a waterdrop in a ocean... I run miners on all my PCs, phones and tablets, so I rarely use my phones for web browsing even though JavaScript support is intentionally limited in mobile browsers, so some annoyances don't work in them.