For this to work, you have to engage an automatic savings plan that sweeps money into a designated savings account at least monthly. DH and I are in the process of putting this together as an alternative to long-term care insurance -- but we have decades for the money to grow.
If you do CDs, I would ladder them in 6-month intervals. What I mean is that you aim to put 20-25% of your fund into a CD at a time, so you have 4-5 different CDs, each one maturing a different month, and as one matures, you move into a new CD). The reason is that we're in a raising interest rate market period, so you want to be moving continually into new CDs as rates rise -- you don't want to be locked into a longer-term CD at current rates, as rates will be higher in 6 months. And higher still 6 months after that. You want to capture the rising rates.
Laddering also ensures you have a little money available for expenses at the end of each month, if needed, without paying a lot of penalty fees. Right now TIAA has very good CD rates. Some credit unions and Internet banks do too -- but "good" is relative, as rates are still at historic lows.
With a dog, the biggest bills are often just 6-10 years away. That's too short a horizon for stock investing IMHO because it's not enough time to ride out stock market ups and downs for any one dog. However, over a lifetime of owning dogs, market investing could work. After you fill your emergency CDs, then I would consider shifting automatic savings into a low-cost, online brokerage account (First Trade is among the cheapest no-frills brokerages right now at around $3/trade; if you need a human to talk to, in a local office, ScotTrade/TD Ameritrade has good service for DIY investers who occasionally like to be able to ask a human a question, around $7/trade).
Here's what I mean by using the market and doing index investing (buying the "whole market"): the market returned over 20% last year, so investing in ultra-cheap, brain-dead-easy Vanguard S&P Index Funds or ETFs (the cheapest of the cheap commodities) returned whopping gains. However, in 2008, the market lost 37%, so these same investors saw their accounts drop that much too. Over time, historically this flattens out into returns in the 7-8% range, and a little higher with dividends reinvested. So take the 10 year span from March 2008 (bad year) through March 2018 (good year), you ended up just under 10% returns with dividends reinvested. The key is that you need TIME though to get that historical return and ride out the bad years.
You have time over a lifetime of dogs, but not any one dog (if a dog's vet needs force you to cash out of the market in a year like 2008, it would be really, really bad).
I recommend never, ever hiring a stock broker for investing. You truly don't need them, and you don't need to be a stock picker or compete with hedge fund pickers. Instead, read any book by James Bogle (his Little Book of Common Sense Investing and Common Sense on Mutual Funds are surely available at any library, as they're absolute classics) -- he shares the passive (EASY) investing strategy for the little guy who knows nothing about stock picking, that simply works for the longhaul, backed by decades of research and data. For what you describe, monthly or quarterly sweeps into a total market index ETF for around $3/trade could work pretty well, if the time horizon is at least a decade (or ideally even longer). Getting money out takes a few days for trades to settle, so this isn't the "might need it tomorrow" fund.
Last edited by Magwart; 03-21-2018 at 11:35 AM.