The knife market has been pretty volatile lately but some skins maintain their value better than others. I started collecting knives about two years ago and learned that pattern index really matters for doppler finishes. Most traders focus on phases but the actual pattern number can make a huge difference in how the colors are distributed across the blade. Factory new condition is obviously preferred but you can find some great deals on minimal wear if you're patient. You should click here if you want to see current pricing trends and compare different float values. What I like about doppler knives is that even the less popular phases still look decent in-game. The key is buying when prices dip and holding until demand picks up again. Never rush into a purchase without checking recent sales history first