I have been changing about 15 gallons from my 75 gallon once a week. Sometimes it's been 7-9 days other times I've done 10 gallons every 5 days. Bottom line is I've just not been consistent every week.

So this is what I've decided to try. Change 5 gallons 3 times a week, Mon, Wed and Fri.

Any thoughts, good bad or other wise?

sounds good rob. your new way will keep your water quality more consistant as it only has 2 to 3 days to muck up rather than going 5 to 9 days then all of the sudden it's cleaner again.

Sounds like a lot of work to me.  Have you had an adverse events in your tank that suggests the tank has suffered from irregular water changes.  It's not like you're waiting a month between?

Depending on how the tank is stocked, maybe 7 to 9 days is fine. 

i don't think it's so much an issue of he has to do it. more that he wants the piece of mind in knowing that he has the best tank husbandry he can reasonably manage

Maybe this is just me not understanding what I've read, but wouldn't you lose/decrease the dilution factor (which is probably not the correct term)?  I saw a chart somewhere that outlined if you had a 100 g tank and changed 10 gallons you would have a 10% change, but the following week, it would have a lesser impact.  In other words, it would not dilute by 10% the second week.  I thought the chart was emphasizing why use RODI water to begin with because if you don't you would never get to 100% RODI water regardless of how many water changes you did.   While use of RODI water is probably not an issue for you, I would think that the benefit of changing the water all at once would be the same, i.e. the biggest impact/increase in quality water. 

On the other hand, it would seem that 5 gallons at a time would be more stable as you aren't making a big change at once so I can see the merit in your thought as well.  If you go with the 5 g option, can you advise us in a couple of weeks whether this is working for you?