Different sizes: Yes, though its all on micro e-minis, depends on the target i’m looking for, the direction of the market, and my risk tolerance for that day. The market is a fickle beast…
Size of Trades affecting trading: Oh yeah. Early on I went in small, then I thought I knew wth I was doing, so I scaled up… and got stopped out, lost a decent amount of money, because i was in TOO BIG and the market went against me. Now i’m down to 10-15 contracts, and even that is probably too much, so I’m scaling back to 5. I’ve made a decent amount and given that amount back, so yeah.
Size of trading also affects emotion, right? Because every tick down you see a freaking red number that is larger than when you take a small position, and it WILL trigger a flight-or-flight response, and no one makes good decisions in that headspace. I was a cop for 12 years and trained on decision-making during fear responses, but that LITTLE RED NUMBER getting bigger STILL triggers a response like a dark-building-with-an-unknown-badguy never could.
Starting small also helps with fills… overnight getting 20 micro e-minis will not run as smoothly as 1 contract. Those fills WILL slip. Slippage sucks. Slippage costs money. Bitten me several times, and I haven’t been trading that long.