i've got a tank about a year & a half old, ... i've never vacuumed the gravel (i wish i used sand - actually i wish i used anything but what is in there now)
it was almost a year before i trimmed any of the plants
i have moved several times over the life of the tank, ...
water changes have been done for moving and medications only
-also an ammonia spike
--a pH that was at 6.5 about ensuring almost all ammonia was converted to safe ammonium
--a major trimming reduced the aquariums ability to process ammonium
--a sudden pH change that allowed for the presence of ammonia
left me with a significant ammonia issue i was ill-prepared to handle.
the point is i have not done water changes for any regular maintenance
water changes are brought about for a very mechanical reason
the nitrogen cycle, ... your fish poops, organics break down, ammonia is released
-bacteria processes ammonia into nitrite (both are very toxic)
-bacteria processes nitrite into nitrate (nitrate is toxic, but tolerable by your fish in low levels)
-water changes to prevent nitrates from rising to dangerous levels
there are 2 ways i know of that can process nitrates into harmless N2
-live rock, ... you can do research on reef tanks to get an estimate on how much coral rock to add to keep your nitrates to always safe levels, i've heard there is lava-rock that can be used for the same purpose
-DSB (Deep Sand Beds) which are of significant depth that the lower levels have negligable O2 levels
both cases it's the lack of dissolved oxygen that allows for a 3rd bacteria that can process nitrates into harmless N2
the other way is to add plants which can take up ammonium directly (if your pH is low), ... if your PH is higher things get processed to nitrates, and your plants can take up nitrates directly.
all these cases toxic nitrogen compounds are removed from the aquarium environment
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the nitrogen cycle issue for promoting water changes
if you have a shallow substrate
if you have no plants
if you are adamant on ensuring no algae,
... then you have no ability to process nitrates, and you will have to change water on a regular basis
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there is a whole science and understanding behind why we have to change water, and what is needed to make water changes optional.
to arbitrarily decide to forgo on water changes is a recipe for disaster
if you want to give it a try on an established tank you have, ... i'd recommend a nitrate test kit to so you can see if things are getting out of control or if things are finding a balanced level
for planted tanks, 20 is recommended 40 is max
for fish, above 10 isn't good
there's a bit of confusion here
what plants want and what fish can handle are vastly different
your fish want nitrates as low as possible
your plants love nitrates and want them higher
... your finding a middle ground where your fish aren't stressed, and there's enough for your plants
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other methods (live rock, a DSB) require a greater understanding & balance, but once in place you can have everything at or near zero for happy healthy fish - not recommended if you have plants as your plants may become nitrogen deficient
so ... you have to pick what is going on in your tank that will allow you to go without water changes
goldfish may eat all your plants
chichlid tanks i hear may have a hard time maintaining plants.
a DSB in a 10 gallon tank is a waste of a tank at 5" of substrate
i don't know enough about live rock and am only hypothesizing on live rock for freshwater as there is very scarce info on it
so not all options are available to everyone
