Bi-Weekly vs. Monthly: The Insider Guide for Kiwi Contact Lens Wearers
27th Feb 2026
Quick Comparison: Replacement Schedules (14 Days vs. 30 Days)
Often called "Bi-Weekly" in the US, these are designed to be replaced every 14 days. This frequent fresh start is ideal for those prone to deposit build-up.
Top Brands: Acuvue Oasys, Avaira Vitality.
These are engineered for durability and are replaced every 30 days. They are the most cost-effective choice for full-time wearers in New Zealand.
Top Brands: Biofinity, Air Optix Aqua Night & Day.
Comparison Table
**Swipe right view the full table
| Feature | Fortnightly (14-Day) | Monthly (30-Day) |
|---|---|---|
| Replacement | Every 2 weeks | Every 4 weeks |
| Best For | Dry eyes & Allergy sufferers | Budget-conscious, full-time wearers |
| Comfort | High (frequent fresh start) | Consistent (requires good cleaning) |
| Annual Cost | Mid-range | Lowest |
| NZ Popularity | Acuvue Oasys $49.95 (6-pack) |
Biofinity ($68.95) & Air Optix Night & Day ($94.95) |
The "Fortnightly" Strategy: Beating the Afternoon Slump
In New Zealand, we call these Fortnightlies (though you’ll see "Bi-Weekly" on the box). These are the "sweet spot" for people who find that their eyes start to protest by 3:00 PM. Because you replace them every 14 days, you’re resetting your eye health before protein, and NZ dust can permanently bond to the lens.
The "Long-Wear" Champion: Acuvue Oasys
The Acuvue Oasys range is a staple for a reason—it’s built for endurance. For many of our customers, it's the only lens that survives the "18-hour day."
What our NZ Customers say
All-Day Comfort
“This lens has been fantastic and I can wear all day and all night without feeling any discomfort.”
— Shelley, New Zealand
The "Invisible" Lens
“Once they're in, I hardly know they are there.”
— Peter B., New Zealand
Reliability
“Always reliable... no matter what the conditions, whether it’s seasonal allergies or NZ's changeable weather.”
— Liam T., New Zealand
The "Monthly" Reality: Maximum Value & Lifestyle Freedom
If you have a complex prescription—such as high astigmatism or presbyopia (needing multifocals)—Monthly lenses are often the gold standard. Because these lenses are made of slightly more durable, thicker materials, manufacturers can produce them in a much wider range of powers and fittings.
Why New Zealanders Choose Biofinity
The Value Choice
“Twentyish bucks a month for the ability to see? How could I not? Upsides are that I'm now immune to Onions.”
— Alex F., Wellington
Sensitive Eyes Approved
“I find these really comfortable and they last and are easy care. I tried other 'better fit' brands that irritated my eyes before going back to Biofinity.”
— Hana, New Zealand
Outstanding Experience
“Outstanding and smooth on the eyes.”
— Luaao T., Canterbury
Some monthlies allow extended wear, such as Air Optix Aqua Night & Day (with optometrist approval).
Hassle-Free Living
“I leave them in for several days at a time... 10/10 would recommend. I love the freedom of not having to worry about them every single night.”
— Chelsea, New Zealand
Zero Cleaning Required
“Fantastic if you hate taking them out each night and using cleaning solutions. I've worn them 24/7 for years, only removing them once a month.”
— Wade T., New Zealand
Which Wearer Are You?
**Swipe right view the full table
| Your Priority | Recommendation | The "Insider" Fact |
|---|---|---|
| Complex Prescription | Monthly | Much wider range for high astigmatism and multifocals. |
| Strict Budget | Monthly | Approx. $20/month; the lowest annual cost in NZ. |
| Long Work Days | Fortnightly | Thinner material; keeps eyes whiter for 18+ hours. |
| Active / Travel | Continuous Wear | Brands like Air Optix Night & Day allow multi-day sleep-in wear. |
| Hay Fever / Allergies | Fortnightly | Binning the lens every 14 days removes trapped pollen and deposits. |
When the Cycle Isn't the Problem: Habit vs. Fit
Sometimes we stick with a lens because it’s "what we've always used," even if it’s not working. We see reviews where users find "supposedly fortnightly" lenses (like some Soflens Toric users) becoming irritating after only 2–3 days.
The Lesson: If you’re changing solutions and still feeling irritation, it’s not the cleaning—it’s likely the lens material or fit. Don't push through the discomfort. As Elle from Auckland mentions regarding her Air Optix: “You have to go to an optometrist to get them fitted right, but once you do, it's worth it.”
Important: The information on this page is for educational purposes only and does not replace professional medical advice. Contact lenses are prescription medical devices. LensesOnline provides lenses strictly according to the prescription issued by your qualified optometrist. If you experience redness, pain, or blurred vision, remove your lenses immediately and consult an eye care professional.
Why Buy from LensesOnline?
Supporting a NZ-owned and operated business means you get more than just great prices. As Jaime (NZ) notes, it's about “great prices and prompt customer service.” We supply the brands you trust with the speed you need.
Ready to restock?
- Shop the Fortnightly Contact Lenses – For that "New Lens" feeling.
- Shop Monthly Contact Lenses – For the best value and the widest prescription range.
We also have astigmatism and multifocal versions.
Frequently Asked Questions
Can I wear a 2-week lens for a month if I clean it well?
No. Strictly follow manufacturer guidelines. Fortnightly materials are not engineered to resist deposits for 30 days. Extending wear increases the risk of eye infections and reduced oxygen flow.
Is "Bi-Weekly" different from "Fortnightly"?
No. They are identical. "Bi-weekly" is the term used in America, while "Fortnightly" is the standard term used in New Zealand.
Do I need a new prescription to switch?
Yes. Lenses vary in material and fit. You should always consult your optometrist before switching between replacement schedules to ensure the lens is healthy for your specific eye shape.