<p>I have been noticing on my trackers that bots are visiting my site ALOT. Should I change or edit my robots.txt or change something? Not sure if thats good, because they are indexing or what?</p>

Should i change or edit my robots.txt or change something?
Depends on the bot. Some bots will dutifully ignore robots.txt. 
We had a similar problem 18 months ago with the google AD bot because our customer was purchasing Soooo many ads. 
Google AD bots will (as documented) ignore wildcard (*) exclusions, but listen to explicit ignores.
Remember, bots that honor robots.txt will just not crawl your site. This is undesirable if you want them to get access to your data for indexing.
A better solution is to throttle or supply static content to the bots.
Not sure if thats good, because they are indexing or what?
They could be indexing/scraping/stealing. All the same really. What I think you want is to throttle their http request processing based on UserAgents. How to do this depends on your web server and app container.
As suggested in other answers, if the bot is malicious, then you'll need to either find the UserAgent pattern and send them 403 forbiddens. Or, if the malicious bots dynamically change user agent strings you have a two further options:
White-list UserAgents - e.g. create a user agent filter that only accepts certain user agents. This is very imperfect.
IP banning - the http header will contain the source IP. Or, if you're getting DOS'd (denial of service attack), then you have bigger problems