I had three kids in three years. It was chaotic. But, I was in "mommy mode" and did playdates, baby classes, etc.I loved it. It was where I wanted to be. My husband worked late and I was on my own with them A LOT!! SO, when my youngest entered kindergarten, I was happy to start back to work and have my own life.
I found out just after I started the process of having my nurse license transferred to my state, that I was pregnant. I can honestly tell you that until that little girl's first birthday, I was in a pretty deep depression. You WANT another, but your oldest is 8. Soon, if now already, he/she will be into sports, music lessons, etc. Carting around a toddler to these things is NOT fun. I am missing out on so much by having to contend for naps, bedtimes, age, etc.
This weekend- my husband and my oldest are going to my son's baseball tournament. We are a family of 6. we can't fit into one hotel room. We are going to "make-do" with it for tomorrow night, but the family is almost always split - to accomodate the baby. We can't go to movies in the theater, we can't spend all day at the beach or amusemnt park....a lot of things...
Your kids will be spaced more evenly, but it still can get to be quite a lot. Your oldest will be 9? when the baby comes. Then, you will have college for these 4 kids- all right after each other. That's another thing we didn't take into consideration(like we planned it...lol!) I had it easy - kind of- when our surprise came along, but I've been thrown back to diapers, bottles, naps, etc It's been a huge change for our family. It's put a strain on our marriage and our finances. It also threw me into such a funk, that it was hard to bond to this little one. Yes, you would be planning for yours and happy to get there. But, you should think of how your life would be in a couple years, when you are doing tons of activities with your older kids and carting along an infant/toddler.
I know I sound harsh. It's taken me a long time to come to grips with this whole thing. I can say that I absolutely love my daughter and she is so smart and adorable and a joy......most the time-lol! My older kids adore her and are GREAT helpers...awesome helpers. It's a struggle and my faith has actually taken quite a hit, also. I'm not sure I understand God's humor......didn't think he was real "funny". But, there must a reason for all this. I may never figure it out, but I will love her just the same. Visualize your life in a couple years. Imagine your 8 yr. old in t-ball, soccer, piano lessons. Your 5 yr old will be right behind.....will they be upset when you can't get to their functions because the baby has to nap/go to bed? Will you feel bad if you have to "pass" on the game/concert because the baby has a cold and can't be carted around all over the place?
If you have a great support system- that will certainly help. We have no family/friends that we can call up and take any of the kids so that we can get a break. The last time we had someone watch our baby, so that we could take the older kids to a movie in the theater...was when she was less than a year old. Last fall, I took my 11 yr old to Harry Potter one weekend, while my husband took my daughter and other son to Mega Mind the previous weekend. We are always splitting up to do things. It works, but it's still such a juggle.
If you have a great itch to have another, you are ahead of the game- I had no itch. But, your husband may have a say in this, too. LOL! It's harder the 4th time around when your older kids are active. For some families, their kids may not be involved in a lot of stuff, or they have grandparents/family around to help - two huge things to consider. IT's not just about the portty training and terrible two's again.
Good luck in your decision!