[patdennis]

1) If you put all of your money in exactly 17 years ago, then, yes. You would be at the same place.

2) It still would've been paying you dividends that entire time

3) If you, rather than investing an imaginary lump sum at the top of the market 17 years ago, invested slowly as your savings accumulated over time, you would be ahead.

The FTSE hasn't exactly been sitting still all those 17 years.

[branchless]

I'm not sure point 3 is correct. Buying regularly would have seen you buy below today's price and above it.

[markvdb]

Dollar cost averaging lowers risk and increases returns. If you can afford it, you may also want to have a look at value averaging.

[branchless]

It lowers risk making returns and/or losses less volatile. It does not increase returns. Of those dumping a lump sum in some lose more some win more and averaging them smooths it out. It's not a magic have your cake and eat it.