I'm looking for the colour of a feature to change based on an input of data in the field. I want to have an attribute "Complete" and when this changes from the default no to yes, I want the colour of the feature to be updated. Can collector do this on the fly?
Yes thats no problem. But you have to prepare your data either in the webmap or (if you use ArcGIS Server) in MXD before exposing to collector. Your symbology can vary depending on an attribute value. Take a look at 'edit symbology' in layer context menu inside the webmap or in layer's symbology tab in arcmap. If you change the attribute in collector the symbology changes also. I recommend the use of domains for a comfortable outdorr editing.