it doesn't matter even the slightest whether you put it all in now or spread it out.
How doesn't it?
I put in 5k right now and buy 500 shares of X... In 4 months the market retreats 20%, my investment is now worth 4K and equivilant to buying 400 shares.
I put in 2k or 200 shares for the next four months and the market does the same thing, I lose $400 of value, but my next contributions have more buying power and over the next four months I am able to buy more shares with my money to level out the losses when the prices increase.
Maybe I'm looking at it wrong. Sure if the market continues to go up, I miss out, but I am somewhat mitigating a large loss.
Again, new to all the investing stuff.