3 seconds seems to be my sweet spot, with my computer.
I usually have two screens/windows open, one for watching the timer countdown and one for entering the bid.
Manual sniping can be risky though, hit confirm bid a second or two too late and the item is gone, sold to someone else.
That's why I quit doing manual sniping, its too fraught with possible problems like slow internet connection, hiccup in ebay's website, wrong price entered, etc. etc. And the need to be up and at the computer (or device) at the very second the bid needs to go in is inconvenient at best, and downright difficult at worst.
As mentioned above, your best friend is a sniping service like Esnipe which I've used successfully for almost 8 years now. Simple, inexpensive, especially when you consider your time and the results if you are really interested in the item and able to bid appropriate and effective amounts. No sniping program is going to help you win if you cheap out on your bid, hoping against hope that no one has seen "your" item but you.
I never reveal my intentions on an item by bidding early. If I have a question, I ask the seller to not put it into the auction page Q&A (but seller has final say on that). Sniping also helps to avoid emotionally charged bidding within the last few minutes, and keeps your heart rate and blood pressure down.
As mentioned, sniping services really only cost a few cents to a few dollars depending on final value winning bid. Some of you mentioned you'd certainly pay a few more dollars if that bid was successful - IMO, the cost of a sniping service is trivial compared to the improvement in success rate, assuming you're bidding correctly.
Otherwise searching for the best BIN or make offer deal also can give you a very good price/performance return.
