I recommend having easy access to your attic. It is preferred to have metal pull down stairs with a platform to access any systems located in the attic. It is important from a safety standpoint that a repair man or you as the homeowner have to attempt to walk on joists or step over ducting to access the systems.
If pull down stairs are not practical, at least have a hatch that is easily opened. If you have any questions regarding this concern, please reach out to WC Home Inspection at 803-448-5512.
I am a full-time home inspector servicing all of South Carolina.