What task planning systems have you used in your projects?

In C# projects, the following systems and libraries are often used for task scheduling:

• Quartz.NET — a powerful task scheduler supporting cron expressions, triggers, and complex schedules.
• Hangfire — a library for background tasks with options for retries, monitoring, and management via a web interface.
• Task Scheduler (Windows) — for running tasks on a schedule at the OS level.
• Timer and Task from the standard .NET library — for simple periodic or delayed tasks.

Example of simple scheduling with Quartz.NET:

IScheduler scheduler = await StdSchedulerFactory.GetDefaultScheduler();
await scheduler.Start();

IJobDetail job = JobBuilder.Create<MyJob>()
    .WithIdentity("job1", "group1")
    .Build();

ITrigger trigger = TriggerBuilder.Create()
    .WithIdentity("trigger1", "group1")
    .StartNow()
    .WithSimpleSchedule(x => x.WithIntervalInMinutes(5).RepeatForever())
    .Build();

await scheduler.ScheduleJob(job, trigger);

The choice depends on the requirements for reliability, schedule complexity, and project infrastructure.