Thursday was World Blood Donor Day and many New Zealanders may be thinking about whether they should take the plunge and give blood.
Giving blood is a noble endeavour as every donation can save up to three lives - and there's even free juice and bikkies at the end.
But as AM Show host Mark Richardson recently realised, just because you want to donate blood doesn't mean the New Zealand Blood Service will take it.
There are several reasons the NZBS may not be able to take your blood due to concerns for your health or the health of the person it's going to.
Your best bet to see if you're eligible is to go to their website and have a look, but here are some of the reasons people could get turned down.
You've had some recent body modifications
That fresh tattoo or shiny new piercing may look great, but if it wasn't performed by a registered health professional, the NZBS says you have to wait six months.
You don't see many pharmacists wielding a tattoo gun though so they're only referring to piercings. If the piercing was done by a professional you're good to go 12 hours after inflammation has settled.
Sorry Mark Richardson, your trip to the UK when mad cow disease was around means you can't give blood. Neither can anyone who lived in the UK, France or the republic of Ireland between 1980 and 1996 for a cumulative six months or more.
On top of that any region where there are a lot of mosquitoes ferrying diseases around could mean a stand down - for example you can't give blood for four months after going to Vanuatu.
The NZBS has a list of all the countries to be wary of and how long you have to wait afterward. It's probably best to consult them for any specific travel.
You're a man who's had sex with another man
This one is controversial, but a fear of HIV dating back to the 1980s means anyone who has had sex with another man has to wait 12 months.
There's also more stand downs if you've lived in a country which is considered to be high risk of HIV infection. Check with the NZBS.
Got the sniffles? Can't give blood. You should also count yourself out for any flu, sore throat, cold sore, stomach bug or other infection.
Maybe you're not sick but somebody in the same house as you is. Better buy your own biscuits and wait until the bug blows over.
How long you have to wait depends on the severity of the bug, but if you have an appointment it's best to call the NZBS and let them know what's up.
So how about the reasons you should give blood?
You're saving lives
Giving blood is literally one of the easiest ways to save a life without really doing that much. Yes, you get pricked by a needle, but all you need to do after that is sit in a chair and wait for those biscuits at the end of it.
You're facing your fears
If you've got a problem with needles, giving blood is a great way to face your fear and save a life at the same time.
Make sure you're super hydrated before you get there to make finding a vein easy and don't look when the needles come out and you'll be fine. There will be plenty of staff around to keep you calm as well.
You could have special blood
A lot of people don't know their blood type. But with some blood types such as O negative being extremely rare, you could have a blood type the country is in desperate need of right now and not even know it.
Just look at Australian man James Harrison. After discovering that his blood had a special antibody, he spent 60 years donating blood to save millions of babies.
And if you don't have special blood? So what! People still need it.