I getting the warning about the jobs in my screen "Too many search jobs found in the dispatch directory" and I was getting rid of them with the clean-dispatch command, starting with the oldest ones, but now I only have todays and yesterdays jobs. Is it OK to keep just the ones from today? or should I increase the limit (limis.conf)?
The number of jobs is dependent largely on how much hardware you have. If you have plenty of space and lots of RAM and CPU cycles available, you can turn up lots of these settings. If you are resources constrained, you don't want to turn up the settings on things like this much because you might start having issues, of course.
If you don't need the dispatch files from jobs before today, I believe you most certainly can get rid of old jobs.