Can I wear a hard hat 13 days after H T surgery?

All doctors will have varying opinions. The only right answer is your doctor's answer who you trusted to perform surgery on your body. I have had patient who are FireFighters, daily motorcycle riders, construction hard hat workers who go back wearing helmets at work is less than 2 weeks without any issue.

I always feel & have noticed that the first 2 week are very critical and next 2 are also not carefree. I suggest you to avoid hard hat and helmet for the time being at least for the first month. Anything hard and heavy will cause pressure to newly grafted area which may result in poor growth. So I suggest you to use some soft cap for now.

Be sure to check with the surgeon who performed your procedure.Depending on the size of the session, number of grafts, post op course so far, FUE vs strip and number of hours per day you will be wearing the hard hat, it likely should be fine at day 13. But please Check with your surgeon. 

We usually supply special trucker hats to all of our patients to make sure that they are clean and can be adjusted so that they are not tight. This is a free service for our patients

Yes you can wear a hat however make sure it is clean and it is not too tight. You can basically return to your normal routine after three weeks of surgery.

In general a hard hat will have straps with a central "button" on the inside where the straps meet. You do not want this pressure on the grafted area, as it will cause graft failure. Remember at 2-4 weeks after surgery your grafts will enter a resting phase that will last from 2 to 5 months on average. These newly transplanted follicles are very sensitive for the first month and should not be subject to continual pressure. This also applies to ski and motorcycle helmets. To mitigate pressure you may wear a balaclava or soft cotton cap after a couple of weeks which helps to prevent direct pressure. This post is for informational purposes and you should always ask your physician for advice directly related to your care.