Just realized a lot of traders don't fully understand how GTC orders actually work, so let me break this down.

GTC stands for Good 'Til Cancelled, and basically it's an order that stays active until you either execute it or manually cancel it. Unlike a regular day order that expires at market close, a GTC order can hang around for weeks or even months waiting for your target price. Most brokerages cap them at around 30 day windows before auto-canceling, though some go up to 90 days.

Here's why this matters: say you think a stock at $55 is overpriced but would be a solid buy at $50. Instead of staring at charts all day, you just set a GTC buy order at $50 and go about your life. When it hits that price, boom, order fills automatically. Same logic works for selling—set a GTC at $90 on a position you're holding at $80, lock in your profit target, and forget about it.

The beauty of using a limit order like this is the automation. You're not glued to your screen, not re-entering the same order every single day. It's especially useful in choppy markets where you know where you want to get in or out, but you're not sure when that level will show up.

That said, there are some real gotchas. Market gaps are probably the biggest one. A stock closes at $60, then opens the next morning at $50 because of some overnight news. Your GTC sell order at $58 just filled way lower than you expected. Earnings announcements, economic data drops, geopolitical events—any of these can create those gaps overnight.

There's also the risk of getting filled on a temporary spike or dip. Volatility happens, and your order might execute at exactly the wrong moment during a brief price swing, right before the stock moves in the opposite direction. And here's something people forget: if you set a GTC and never check on it, market conditions can completely change and your old strategy might not make sense anymore. That order just sits there until it fills or hits the 30 day expiration.

Compared to day orders, which expire by market close, GTC orders give you way more flexibility for longer-term price targets. Day orders are better if you're chasing short-term moves and want to limit your exposure to just one session. But if you're hunting for a specific price over days or weeks, GTC is the move—just remember to periodically review what you have sitting out there.

The key is being intentional about it. Set your levels, understand the risks, and don't just forget about orders hanging in the system. That's how you avoid nasty surprises.