I was very hesitant at first before buying out first
canister filter.
Never had them leak so far.
I think a large percentage of leaking is due to operator error, poor maintenance or not giving the filter a good visual inspection after taking it apart for cleaning and before putting it back together to run it again.
Some good insurance is to buy a set of stainless steel hose clamps to secure the hoses to the hose barbs on the intake/discharge pipes and at the connection points on the motor head. This will ensure the hoses dont slip off and will give them a nice tight fit.
Also, I like to run a q-tip over any o-rings, seals, and gaskets to clean them off each time the canister is removed for cleaning. Doing this cleans the rubber surface and also gives you a chance to visually inspect the rubber surface. Look for nicks, gouges, tears or deformities on the rubber.
Afterwards, I will use new q-tips or my finger to apply some food grade
silicone lube on the rubber. Danco Weatherproof Grease and Superlube Oring Silicone Grease are options, but there are dozens to choose from.
Also, not being in a rush and taking your time while disassembling and re-assembling the canister will help prevent leaks.
Sure there are times when a canister component will fail and could not be prevented, but those are rare.
Or you can just skip using a canister filter and use a pair of large
sponge filters and a good sized
HOB filter.
For example our 65g community tank only has a single large sponge filter, a
Tidal 75 and a Top Fin Silentstream 75. Water always stays clear and cycled properly.