Ever placed an order and then forgot about it for weeks? That's basically what a good til cancelled order is for. I've been using GTC orders for years now, and honestly they're one of those trading tools that can save you a ton of time if you know how to use them right.

So here's the deal with GTC orders: you set a buy or sell price, and the order just sits there active across multiple trading sessions until either the price gets hit or you manually cancel it. Unlike day orders that die at market close, a GTC order keeps working in the background. You don't have to babysit the charts every single day waiting for your target price.

Let me give you a practical example. Say you think a stock at 55 bucks is overpriced, but you'd jump on it at 50. Instead of staring at your screen all day, you just place a GTC buy order at 50 and go about your day. When it finally drops to that level, boom, the order executes automatically. Same logic works for selling too - lock in your profit target with a GTC sell order and let the market come to you.

Now here's where it gets tricky. Brokerages typically auto-cancel these orders after 30 to 90 days to prevent stale orders from cluttering the system. But that's not even the main risk. The real danger is market volatility and gaps. I've seen traders get burned when a stock dips briefly due to noise, filling their GTC order right before it crashes further. Or worse, overnight gaps - stock closes at 60, opens the next day at 50 after earnings, and suddenly your GTC sell order at 58 executes way lower than you expected.

The biggest mistake people make is setting a GTC order and then completely forgetting about it. Market conditions change. Your strategy evolves. That order sitting there for months might trigger at exactly the wrong time. I always review my open GTC orders every couple weeks and adjust if needed.

Compared to day orders, GTC orders are built for patience. Day orders are your move if you're hunting quick price swings in a single session. GTC orders are for when you're targeting a specific price over days or weeks and you're willing to wait. One isn't necessarily better than the other - depends on your trading style.

The bottom line is GTC orders are solid for automating your trading without constant monitoring. Just remember they come with real risks - market gaps, unexpected volatility, and the risk of forgotten orders executing under changed conditions. Use them smart, review them regularly, and they can be a solid part of your toolkit. Just don't set it and forget it completely.