You can assign your job custom fields to a specific service. This essentially gives you the power to build customized forms for different types of jobs.
Setting up custom fields
For example, imagine a pet service that walks dogs, feeds pets, and also offers full in-home pet sitting.
The Custom Fields setup screen now looks a little different. Fields appear in a single list and can be filtered by type, or by which object they belong to (Job or Customer).
When you create a custom field and select Job as the parent object, a new dropdown containing your services will appear.
If you select a service from the list, this field will only appear on jobs of that type of service. Here's the Additional Information section for the Pet Sitting service:
And here it is for the Dog Walk service:
Note the View all custom fields control at the bottom. Clicking that will bring up a list of all available custom fields, not just the ones specific to this type of job. You can always enter a value for any field you like. Any custom field you do not assign to a service will appear in this list, and you can give any of them a value if you like.
Existing custom fields
If you used custom fields prior to this change there's a catch: existing custom fields with data in them cannot be assigned to a specific service type. For the pet sitting example above, let's say you had the Number of pets field already set up, and used it on some dog walking jobs, some pet sitting jobs, and some feeding jobs. It wouldn't make sense to retroactively limit that field to only one service type. So, if you try to edit a field that already has some data in it, you'll see a warning, and some options will be disabled.
You'll need to create a new custom field, assign it to the service you want, and use that one moving forward. (Be sure and rename the old one to avoid confusion.) If you want, you can create a custom report to see what jobs are using that field, and either delete the data or move it into the new field.
You don't need to worry about running out of fields here, because you have unlimited custom fields at your disposal. So go ahead and make as many as you need.