I have a lot of fun skrittering and whenever I am bored I'll just come here and practice even when I have 0 due. Sometimes for hours a day and this pushes the times between reviews pretty far apart. Is this going to hurt me any?

just add more characters or words?

I'll have added like 100 words in that two hour span and got them wrong the first 50 rimes before they sink in. Wont I just get overwhelmed? I have no problem adding like 50 words all at once and just plugging away until I finally get them right, but I'm worried this is going to mess up the algorithm.

hmm I think the algorithm should be able to handle that, but I know what you mean...me for example, I add 16 characters a day (to achieve about 2200 characters in 5 months), but the daily study time varies (at least right now) between 15 and 40 minutes, so I would have to overpractice to achieve 20min for the competition some days...so basically I plan enough time to skritter and then do something else instead of overpracticing... there are other fun things in life, too ;-)

The scheduling algorithms are flexible. If you overpractice, even by a couple hours, it will not be a big efficiency hit unless one of two things are true:
1) You don't have many long-term reviews, or
2) You do it a lot without adding enough words in a longer time period.
You can use the readiness indicators in the prompt to help guide you. If you see something like "80% due" in small grey text, you're fine. If you are getting down toward 50-60%, then you're probably taking a noticeable efficiency hit, and if you want to keep practicing then, it will be better to add new words.

Note that adding hundreds of new words and then not coming back again soon to study them would be the opposite of this and also could hurt your efficiency, so that's why you might not want to over-add.

Thanks for the explanation. You guys rock.