I have a 2000 Corolla CE with 196,000 miles that I bought new off the lot. My oil consumption has been high since about 80,000 miles. I'm now at the fill with oil and check the gas stage. I am getting about 400 miles per quart. Still runs like a top though and plan on keeping it and feeding its oil habit. I'm getting 32+ mpg in mostly highway miles.
I've done all oil changes except the first one. I ran good quality oils, mostly synthetic until I started having to add 2 plus quarts every OCI.
I now look for sales, and buy three 1 gallon jugs when doing an oil change. One for the oil change and two for keeping it filled for the next two months.
Other than brakes, tires, oil, and fluids; I've only replaced the plugs, cat convertor, and rear O2. I'm running the original water pump, coolant hoses, etc.
Its beginning to leak a little oil around the crank pulley a bit, but most of its consumption is out the tail pipe.
What I learned here, mostly, is that trying to fix this isn't really cost-effective.
jim