A single Jenkins instance can contain many jobs. The practical limit varies widely and depends on multiple factors, such as the following:
Hardware resources such as RAM, CPU, disk, and network performance
Slave nodes—how many there are, how they are set up, and their performance
How well the jobs are distributed across the Master and Slave nodes
Settings of individual jobs; their size, function, history, and retention
It's not unusual for a Jenkins instance to have over 1,000 jobs, or around 100 Slave nodes attached to a Master node.
Managing the performance load that this causes is a big task in itself, and Jenkins also needs to manage the presentation and housekeeping of these jobs—your users will not want to look through more than 1,000 jobs just to search for the one they need, and we also need to make sure that old jobs are cleaned up or archived and that new ones can be created both easily and accurately.
If you can reduce the number of jobs you...