When I first started, I didn't really factor in humidity and temperature. My game changed once I purchased a hygrometer (sometimes confused with a hydrometer) to measure my environment.
If you understand how essential it is to control/track your humidity and temperature, you will understand how essential a hygrometer is.
Use this baby to ensure your environment is optimum for your glues drying time.
Place this as close to your client as you can to ensure accurate readings.
Batteries not included.