The toilet is suspect #1 as it is relied on a daily basis to push gallons of water and matter through its system as well take the full body weight of us humans.
Taking a dry cloth and dragging it around the base and checking for any water build up or leaks. Identifying leaks early can save you from having to replace the floorboards below, a far greater expense than a new toilet or rubber rings. If you do find leaks, it's time to call your plumber.
We've spoken to a dozen plumbers who have the same advice -- don't put hot water or 'cleaning' agents into your toilet. It will break down your plumbing and rubber rings faster. Normal dish detergent is enough to clean the insides and scrubbing the hard-to-reach jets will improve flow.
With the dry cloth, run it along the base of the tub. Make sure that the caulking is water-tight with your bathroom floor. If there is any separation, immediately re-caulk any gaps.