Okay this is a topic I have researched a lot about as my dad has swimmers ear really badly and I started preventing it for myself 10 years ago.
First thing is to check the water temperature at your break. From my experience you will not have a problem until the water reaches under 19 degrees. You will notice that your ears will not drain out the water in the first couple of duck dives. In sydney this happens around late may till end of september. Always wear pugs in this time doesnt matter which, swimming, blue tac etc.
The wind will increase the problem, so if its windy wear a hat, ear hoodie, gath etc, If your heads small get the neoprene cover for your ears.
After swimming you will notice if your ears don't rinse out. Then use a ear clearing mixture. I like the earclear (yellow pack). It is mainly Peroxide and pop it in each ear for 1 minute. You may need to do this twice at night after you have been in cold water. You can use ear clear (alcohol based) to protect your ear before a surf but I found plugs work better. Its also called viscol I think.
When the water warms up in spring use the ear clear maybe twice a month to just maintain the wax and sand build up in your ears. You will not need the plugs.
This is for surfing or surf swimming.
On the sup you should be fine. How much are you in the water? I would recommend a hat with ear protection as the wind is your main problem. I like the FCS sup hat from sup the creek.
I have two one from BCF that is for the sun and covers me totally except my eyes.
http://www.bcf.com.au/online-store/products/SunProtection-Australia-Adapt-A-Cap-Unisex-Marine-Camo-OSFM.aspx?pid=37603902#Recommendations.The other is an Outdoor research Seattle sombrero wide brim with polarfleece to keep my head warm from canada.
www.outdoorresearch.com/en/seattle-sombrero.htmlThe more you keep the ear clean of wax and sand the less maintainace you will need. Keep on top of the ear cleaning routines.
Surgery is expensive, invasive and hardly ever improves with drilling of the ear. My dad cant hear the tv under 40 on the volume. That is loud.
My advice would be to go and buy four sets of plugs and two bottles of earclear. This will save you big money in the long run.