Balance varies by the person. Some people are able to take on more because of their personalities, their organizational skills, their time management skills and their energy levels. A good way to evaluate it is to jot down your priorities in order. Usually for me they go something like this:
God (personal relationship)
Personal (my own health and wellbeing)
Family (basic responsibilities + quality time)
Church (basic responsibilities + ministry responsibilities)
Extended Family (staying in contact + occasional visits)
Friends (quality time)
Community (involvement & outreach)
Everything else
It really boils down to how much YOU can handle without neglecting a higher priority. I don't neglect my family in favor of church and I don't neglect church in favor of community involvement. I don't neglect God in favor of family and so on and so forth. Of course, in reality, I DO neglect my responsibilities sometimes, because we do tend to have to struggle for balance. In order to be sane and balanced, we have to re-evaluate every so often and make sure we haven't overloaded ourselves and moved something important out of the way for something less important.
I feel that my personal relationship with God involves attending the church for corporate worship and the Word, and giving my tithes and offering. IMO, that is the extent of the crossover between my personal relationship with God and my obligations to the church. I also believe that my personal relationship with God and being a part of His kingdom requires me to be *reaching out* evangelistically as a Christian. However, the latter doesn't have to be accomplished through a church program. That is accomplished by taking Christmas gifts to neighbors and striking up conversations with strangers at the grocery store. For ME, church obligations or ministries that exceed what I have outlined as my personal obligations to God fall into a category that is less important than God, Personal and Family priorities. I don't accept church responsibilities that I can't fulfill without keeping those first responsibilities going effectively.
My personal rule of thumb is that my commitments are good for one year. At the end of every year, I look at my schedule again and decide whether or not I can recommit to music department, teaching, various outreaches, music camp, etc. These are decisions that I make with my husband's input, and then I inform other people of those decisions. The reason for the 1-year commitment is that it inconveniences other people and departments to lose key people or leaders in the middle of the [fiscal] year. It's a way to be considerate. It's also a way to make sure you are really certain you want to commit to a department for a full year before you say yes.
Bottom Line:
It's okay to say no.

And no one's salvation is dependent on their involvement in church programs, fundraisers, etc.
Ever.