I just got back from RAGBRAI 2016 and went to upload all 7 days of riding from my older Garmin edge 305 to my computer so I could upload to strava. I noticed that day 1 and 2, even though still on my unit with miles and stats in the history, was blank when I uploaded to strava. Apparently the device ran out of space and over wrote the first 2 days. I keep the unit cleaned out so it had no other history in it prior. Is this what I can expect in the future until I can afford to upgrade? I guess I could have taken my lap top along and tethered it each day then deleted my ride from the unit. Suggestions?

Shouldn't have happened. I suppose the unit's memory could be going bad. Could also be corrupt save files. You have no ride record files to work with at all on the unit from those days?

Yes I could still look on my unit and get the miles and time and create a manual activity on strava but since the track was gone I had no elevation data and certainly no course track to show