A willingness to learn basic lab/darkroom skills and the acceptance that care and repeatability are important. Good ventilation. Tools: Safelight, digital thermometer, tempering waterbath on magnetic stirring hot plate (I found my venerable darling on eBay for $149). Glass burette with stand, hot plate (I was using the base of a slow cooker before I got a "real" one for Christmas.) A reliable electronic lab scale, graduated cylinders, plastic injection syringes (Monoject 412). Small flashlight shielded with red safety film. An assortment of containers - beakers, baby food jars, canning jars, plastic condiment cups. Collecting the perfect container is part of the fun.
An few important things to know if you're just getting started: You don't have to have it all at once, almost none of it has to come from a photography supplier, and almost everything can be substituted for a kitchen or dimestore facsimile.