Been trading for a while and realized a lot of people don't really understand how a good till cancelled order works - so figured I'd break it down.

Basically, a GTC order (good till cancelled order) lets you set a buy or sell price and just... leave it. Unlike day orders that disappear when the market closes, your GTC order hangs around across multiple trading sessions. It stays active until either the price hits your target and executes, or you manually cancel it. Most brokers will auto-cancel after 30-90 days though, so they don't sit forever.

Here's where it gets practical. Say you think a stock trading at $55 is overpriced but would be a steal at $50. Instead of staring at charts all day waiting for that dip, you just place a good till cancelled order at $50 and go about your day. Price drops to your level? Order fills automatically. No constant monitoring needed.

Same logic works for selling. I've done this plenty - holding something at $80 and setting a GTC sell order at $90 to lock in profits without babysitting the position. When it hits $90, it executes. Clean.

But here's the thing - and this is important - a good till cancelled order can bite you if you're not careful. The automatic execution is convenient until it's not. Price can spike or dip unexpectedly due to volatility, and suddenly your order fills at a moment you didn't anticipate. Worse, you can get gapped. Stock closes at $60, reopens at $50 the next morning after bad news, and your $58 sell order executes way lower than you expected.

I've also seen people forget they had open GTC orders sitting around. Market conditions change, your strategy evolves, but that old order is still lurking and executes under circumstances that no longer make sense. It happens more than you'd think.

Compare this to a day order - which expires at market close - and you see the tradeoff. Day orders are safer if you want short-term precision and control. Good till cancelled orders are better if you're hunting for a specific price level over days or weeks and don't want to re-enter the same order repeatedly.

So if you're using a good till cancelled order, actually check on them periodically. Don't just set it and forget it completely. Review what you have open, make sure the logic still makes sense given where the market is now. Some traders use stop-losses alongside their GTC orders for extra protection.

Bottom line: A good till cancelled order is a solid tool for automation and patience, but it requires some awareness. Use it when you have conviction about a price level and can accept the risks of automatic execution. Just don't let it become a ghost order haunting your portfolio.