Say I made text, extruded, then made it into a mesh to add an effect to it (like dissolving or something). Is there a way to edit that text again while retaining the effects/modifiers that I had applied to it? Or once I make a mesh out of it is there no going back?
Thanks in advance
nope, unfortunately there’s no going back, Once its converted to a MESH theres no way to edit the text/font
you will just have to try to remember the steps you took and try to do it all over again 
Like @Lgowans said you can’t edit a text thats converted to a text. You could fiddle with it in edit mode and make the correction via a new text object and then join them again but thats too much work.
For the future, I would recommend duplicating the text object before converting it to a mesh. If you need to edit the text you can edit the backup object and then convert that to mesh and then copy the modifiers using Ctrl - L.