EDIT: IGNORE THIS POST, its all wrong.

The smaller pip gain/loss, the more your transaction costs will eat up any profit.

Example 1:

if u close trades at +/- 10 pips, and spread is 1 pip cost(eur/usd for example), then 10% of your trade is transaction cost.

If 1/2 of your trades are losers, then transaction costs will be 20% of your winning trades.

That would mean that your analysis would need to show 70% winning trades just to break even. (This seems craaaaaazzzyyy to me, no wonder people kill their accounts)

Example 2:

if u close trades at +/- 100 pips, and spread is 1 pip cost(eur/usd for example), then 1% of your trade is transaction cost.

If 1/2 of your trades are losers, then transaction costs will be 2% of your winning trades. That would mean that your analysis would need to show 52% winning trades just to break even. (This seems much more possible)

Example 3:

if u close trades at +/- 1000 pips, and spread is 1 pip cost(eur/usd for example), then .1% of your trade is transaction cost.

If 1/2 of your trades are losers, then transaction costs will be .2% of your winning trades. That would mean that your analysis would need to show 50.2% winning trades jto break even. (Almost as good as a coin flip!)

As long as you have lower leverage, (account exposure/account balance) you have a much better chance of being successful and not being eaten up by the spread.

The spread is the silent killer of accounts!

Edit:If you pay even a 2 pip transaction cost, then the numbers get even worse!

Example 1: 90% of trades needed to be winners(OMG!)

Example 2: 54% "

Example 3 50.4% "