To add on the accuracy discussion, let me make a suggestion:
Set up a custom screen on your 305 (or 205) and have one of the fields show GPS accuracy. Anything less than 40 feet is very good. Anything less than 30 feet is excellent. Some places you'll get less than 20 feet. Where I live, it is unusual to have an accuracy under 30 feet once I get running.
[note: edited to say "under" 30 feet instead of "over"]
Whenever mine shows less than 30 feet consistently I can count on each mile split being within a couple seconds (less than 1/100th of a mile) of being right on. But if I am running and I see that GPS accuracy field being too high, I know that I probably need to take what the Garmin says with a grain of salt.
This will help to remove the doubt.
Set up a custom screen on your 305 (or 205) and have one of the fields show GPS accuracy. Anything less than 40 feet is very good. Anything less than 30 feet is excellent. Some places you'll get less than 20 feet. Where I live, it is unusual to have an accuracy under 30 feet once I get running.
[note: edited to say "under" 30 feet instead of "over"]
Whenever mine shows less than 30 feet consistently I can count on each mile split being within a couple seconds (less than 1/100th of a mile) of being right on. But if I am running and I see that GPS accuracy field being too high, I know that I probably need to take what the Garmin says with a grain of salt.
This will help to remove the doubt.