What is the etiquette or rules for this ?
eg Any limit to reposting previous obs etc ?
It is not a problem lot's of people do this especially in the winter months when the site is much quieter hopefully the photo's are of decent quality as it is hard to id some things if the photos are bad.I have a couple that I will be putting on from the summer and some obs are from up to 6 years ago.Look forward to seeing the observations and hopefully iSpot will be able to help confirm or identify your photo's
No specific rules I am aware of. Out of season seems fine, just make sure you set the correct date so people are not confused.
Reposting previous obs could be seen as cheating a bit (getting two lots of reputation for the same observation) but if it is something you did not get identified last time then that is probably fine (personally I would go and delete the old version of the record if I were to do this).
 There is an odd iSpot feature where the metadata from the photo (which might be when you edited the picture) replace the date you have entered in certain circumstances.
You must have taken more notice than me I never saw the repeat ob's but as you say if it has not been Identified I would state that you have put it on and when then remove the previous observation.
My query was prompted by a couple of things.
First that it seems rather jarring to have pictures of summer insects (or whatever) sunning themselves on green leaves in the middle of November. I thought that ispot was a "what are you seeing in your suroundings right now" kind of thing.
However, if not, then I have a number of previously posted - but unidentified - species from earlier in the year I'd like some input on.
Am not keen on deleting previous entries though. What might be useful is the facility to "lock" the previous obs with a link to the repeat posting. For now I will probably just put a comment to that effect in any repeats.
Just to add re photos, the exif data seems to be coming through fairly reliably for me as date taken. Am quite careful with that.
Not sure that iSpot has ever been very narrow in specifying its purpose.
I would say it is more of a "help with identification" thing rather than about current observations per se. Certainly when I first joined I went back through some of my un-IDd photos to give them another go.