While not a necessity, I think trail cams do give you a good idea of what's running around your hunting area while you're not there, and sometimes when you are there, as this pic shows. This is an 8ptthat I could/should have shot (10yrds) veryearly on in our Pa season. He walked right past my cam after he got his walking papers.I knew there were a couple of bigger bucks (via trail cam) in my area so I wasn't too concernedat the time. I do however, still have my buck tag.
Like some have mentioned previously, I think the biggest mistake folks make regarding the use of trail cams is they tend to check them too frequently. I've found that once every two weeks is sufficient. I think they're a lot of fun, and something to look forward to.