***"I'd think bigger is better but do not want to harm anything."***"275ca / 230cca OR a 350ca / 290cca."***
The CA & CCA ratings of the battery are indicators of a battery "storage and delivery" capability only. That ostensibly means that you stand less chance of doing harm to a starter if you choose a battery with a higher CA/CCA rating because that "bigger" battery will have a higher average power potential (and standing voltage) when called upon to crank the engine. A higher CA/CCA will not harm your alternator, the alternator has a maximum output and is quite safe and happy operating at its maximum output, 100% duty cycle if need be. A "battery tender" or "battery maintainer" type of charger is highly popular with owners of seasonal use OPE to keep the battery charge level near its optimum voltage. I suggest you do a few "topic searches" on this forum to get the most info possible as this subject has been aired quite often. The link below will give you results for just one search I used with "Battery maintainers" as the search words.

Here is a link that might be useful: Just one of many possible

You don't use the tractor during the winter months and that's when CCA ratings really matter because the colder it gets, the harder it is to start an engine.

If I were you, I'd just buy the lowest priced battery I could find and then use a battery maintainer on it as Mownie suggested, to keep it at full charge when the tractor is idle. If your tractor's engine is in good tune, then it will start almost instantly. Prolonged use of the starter motor won't be an issue. Cold weather stiffening the oil and engine parts won't be an issue and cold weather causing a performance decrease in the battery also won't happen.

All lead/acid batteries begin to deteriorate the second electrolyte is added to them. Buying a battery with a high CCA rating does not guarantee that the troughs under the cells are deeper than those of the low cost battery. When the troughs fill up with plate material, the cell shorts out and goes dead.

But if it makes you happy to buy an expensive battery for your LT, then it's your money when it comes down to the decision.

I found the biggest bang for the buck (CCA vs Cost) was an autozone battery (if you believe the stickers on the battery?). for around 21 bucks had about 300 CCA. Vs the 165 to 230 at wally world (less face it wally world has some cheap Shyt)(thats why there prices are same or lower IMO of course).

I agree with the above high price (brand name) don't always mean bigger or better battery. It only takes about 100CA if that to crank LT engine. The only benifit IMO for a larger (CCA) is if you have to crank it ALONG time otherwise a small (low CCAs) cheap battery will start it just fine, sometimes the accessories or attachments you run like a sprayer that runs off battery power may pull to much amps for a weak old battery and naturally the more plates (heavier the battery) the more sustained voltage is available provided the engine charging system can't keep up.

A new battery reguardless where you get it will work just find, Just make sure you hook up the cables right cause some posts maybe oppisite to your old battery.

I bought the higher CCA at Sam's club. Its an Energizer....on the label anyway. The thing started right up. Thanks for the winter advise. I NEVER did anything but park the tractor in the shed and it always started the next year. I checked and my battery would have been 4 years old in Nov..I guess I was looking for 6 years like the OEM...maybe I just got lucky in that one.

So, to clarify...do I ever check the water level and do I ever add water...?

The battery in your tractor and in car is one of the most important, least expensive, most abused, least understood things. We depend so much on it yet we try and push it more and more. When it lets us down, we immidiately want to change vendors and we look for the purchase invoice in the event its still under warranty. My advice has always been , get a good battery (whatever brand you like-shop around and get it on sale,) keep a battery tender on it when not in use for long periods of time, and in 5 years, get yourself a new one and repeat the process again. With this system, you will ALWAYS have a working battery. A $30 tractor battery ends up being $6/year. We are talking 6 bucks now. Thats about two slices of pizza and a soda. If you don't do this,the minute the temperature hits 20 degrees out , you will be reaching for the ratchet set and running to sears to get whatever battery they have in stock at whatever price.

Yes, if your battery is not the sealed type--if it has caps on the top of it--yes, you should check the water level occasionally, especially if you do a lot of starting and shutting down. And--do not use city tap water! Buy a gallon of Distilled water at the store, and also buy a "Turkey Baster" to use to inject the water into each cell. Do not use it for anything else! And, if ya don't know what a turkey baster is, any good hardware store person worth their salt can show one to you.
Inject enough water to cover the tops of the plates by a quarter inch or a bit more, but not to the tops of the fill holes! I fill mine to the bottom of the fill holes. You will know when you get it right, by looking for the dimpled look of the water.