I can be neurotic about keeping track of which plants I have and where they are planted.
I hear ya. I'm also a neurotic tracker of plants...
Those markers look nice but they are too pricey for me
I recently hosted a garden tour and I had nearly two hundred of the zinc metal plant markers out to identify the less common plants. I used a very fine point paint-pen that I got from an art supply store to write on the markers. The ink (paint) reportedly will last for many years and it comes in various colors. I then pull up the markers after the tour and store them. Some of the plants are not easily identifiable by me and for those plants I leave one of those white plastic markers in the ground next to the plant so that I can easily identify it when I need to put out my metal markers. I don't mark the location of small bubs such as paperwhites and daffodils but I have a general idea as to where they are. However, sometimes I will see a bare spot and try to plant something there only to find a bulb is already an established occupant.....
To help me keep track of my plants I keep a Word document on my pc that has the botanical name, common name, physical description of the plant and additional notes of interest (e.g., full sun, shade, acidic soil, place of origin, where planted etc.) of all my plants. As soon as I purchase a new plant I Google the name of the plant and then record the information about the plant in this document. During the garden tour I kept this document with me in case someone had specific questions about a plant.