Timex® does have the watch that "takes a licking, and keeps on ticking," but one can't say the same about the watchband. It's not unusual to have a Timex® for 10 years or more but a band that will probably need replacing about every 18 months.
Find the right tool. A mini-screwdriver or other tool kit---such as the Wiha Microbits---works great.
Figure out the correct watchband size. Most watchbands are sized from 12 mm to 18 mm, so you need to know which measurement to use when buying a replacement. A Sizematic™ measuring system can be downloaded. Print it out at 100 per cent and measure your existing band against its key.
Know the configuration for removal. There are two lugends---metal bars---that are part of the watch the band fits between. The watchband is held in by a small circular bar. At each end of the bar is a spring-loaded pin clasp in a sheath. Remove the old watchband by taking a small screwdriver and pushing one end of the sheath pin inward. Slide the pin out of its hole in the lugend; the watchband will slip off the bar. Do each side.
Slip the new watchband onto its spring-loaded bar pin. Make sure it is facing the right direction. Place the band between the lugends. Put one end of the pin into its hole in the lugend. Compress the end of the spring-loaded sheath inward on the other side of the band with your tool, and when the pin is revealed, place it into its hole.
A pin-compression tool comes with some watchband purchases, but a good mini-screwdriver will do the job. A jeweller uses a notched tool to work the pin, but he will charge a fee to change the band. Timex® batteries are expected to last five years; if you've gone through four or five watchbands, you might want to change the battery at the five-year mark. Target sells a special pad to use when working with watches, mainly for changing the battery. You can download Timex® instructions on how to remove links in a link-bracelet-style watch and how to adjust the band for smaller wrists. There also is an explanation about changing batteries and more. Cooltools.com has some terrific mini-tool reviews---one multipurpose product will even go through airport security because it looks like a key.
When all else fails, you can send the watch into the Timex® service department.