We are not part of a co-op, but my sister Cindy was for awhile and enjoyed it for most of the years she was involved.
For us, HOD already beautifully meets our academic needs, so we would only join a co-op for social reasons, or possibly for 1 day a week for fun academic activities. The co-ops around us are too heavy on academics for our needs - they would require too much time and double up on subjects/skills we are already covering well with HOD. So, we instead get together with cousins one afternoon each week for social needs. For extra fun academic type activities, we follow each of our dc's interests and invest in things that fit them. For our family, this has worked better than being a part of our local co-op. However, my sister Cindy (in Texas) has been part of various co-ops throughout the past 20 years and enjoyed some through the years, and dropped some through the years, for different reasons. Basically, co-ops exist for all different reasons. If you join a co-op with goals that match the needs you have, you have a good fit.
If you join a co-op that has different goals than you have, it is not a good fit.
So,the first question to ask is, IMHO, is what is the purpose of the co-op?
*academic
*social
*both
The next question to ask is, what are you hoping the co-op will do for you and your family?
*fill an academic need
*fill a social need
*both
The last question is, will it interfere with your ability to homeschool your dc, or will it be a part of a balanced plan for them and for you? Considering HOD is written as a full, balanced, complete curriculum already, extra academics that extend beyond the one day off each week already planned for in the upper HOD guides, will probably tip the balance to the too heavy side of academics. Specific questions when considering joining a co-op might be...
*Will you or your dc's responsibilities in the co-op interfere with your being able to homeschool well? (i.e. Do you need to teach classes that may end up taking precedence over teaching your own dc well at home? Do your dc need to take classes that may have homework that ends up taking precedence over their being able to do their work for HOD well at home? Will funds be spent on the co-op that interfere with you being able to afford the books, resources, and materials you need to homeschool at home?, etc.)
*Can you still make homeschooling your dc as their teacher at home using HOD enough of a priority that you can complete about a guide or so a year? (Or whatever pacing best fits your dc's needs academically)
*Will the co-op have too much rigor that causes stress for you or your dc because your day is overloaded? And will you possibly then be skipping things in the HOD guide that really do need to be taught?
*Are you joining the co-op for social reasons, but really the co-op is also based on academics? Or vice versa?
The reason I pose these questions is because through the past decade I have seen many families join a co-op to fulfill social needs only to find out the co-op instead heaped on academics. This threw everything out of balance, and suddenly important things were getting skipped, stress was through the roof, and someone besides 'mom' was becoming the key teacher in dc's lives. On the other hand, other families LOVE their co-ops, are getting all of their HOD done consistently, and find the co-op to fill a need they have in a balanced, wonderful way!
So, I guess I would say, as with anything, it is pretty important to do your homework.
Look at the kinds of activities, time commitments, and homework the co-op you are considering joining may require. Try to have realistic expectations going into it. In other words... Don't expect an academic co-op to fill a social need you have, and don't expect a social co-op to fill an academic need you have. On the flip side... Do expect an academic co-op that takes more time than you or your dc have to be too much academically, and do expect a social co-op that takes more time than you or your dc have to be too much socially. If a co-op is both a social and an academic co-op, try to weigh whether the 'extra' part of it that you don't really need is worth the added time and commitment it will add to your life. Or, see if you can choose to opt out of the extra part you don't need and only participate in the part you do need.
Co-ops can be a beautiful thing, can fill important needs, and can be something you look forward to each week. Or, they can be stressful, can be tough to quit, and can be what causes homeschooling not to get done. Only you can know which is the case for your family and for the co-op you are considering!
Hope something here helps!
In Christ,
Julie