I usually use a timer, but there are periods of time when I don’t want the jarringness of a sound to end it. Then I’ll use a mala, moving one bead for each breath. You can use it with your timer a few times, and get an approximate idea of how many cycles your standard meditation length is. If you use two of the short bracelet style or a Jodo Shu style juzu, then each time around the first string is one bead on the second string. You can set your time by where you hold the second string at the start of your session - hold it so that you will count the correct number of beads before reaching the guru bead.

For really long sessions or when counting short mantras, use the hanging beads to count times round the second string.

I always use a timer to start off but sometimes will switch off the timer and continue meditating for an unspecified amount of time on days where I feel up to it.

Without a timer I tend to start wandering off into thoughts about whether or not I’ve been meditating long enough, and I find that incredibly distracting from the process. When I know I have a timer/alarm going off at the right length of time, I can put my mind to rest and not think about how long I’ve been meditating.

Also if I’m getting back into meditation after a period of not keeping up with it, I sometimes break my meditation down into smaller chunks. Even though I meditate for the same length of time, having alarms spaced closer together makes me feel like it’s taking less time, so eases me back into longer sessions.