Detect Arcane Residue

For the duration, you can sense residual trails of magic left by magic items or spells that were used within 30 feet of you location in the last 24 hours. The older the trail, the fainter it is, spells of higher levels or rarer magical items leave a stronger residue. You are able to roughly tell how old the trail is, and in which direction it travels, if any. The trails of magic glow different colors depending on the school of magic that was used. 

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher you can detect older residues and trails, one week at 3rd Level, a month at 6th Level, six months at 8th Level, one year at 9th Level.