When the kids are gone, a four-bedroom house stops being a family headquarters and slowly becomes a maintenance project. Most people I talk to aren't unsure whether they want less house. They're unsure whether now is the right time, whether they can give up the interest rate they have, and how they'll feel about leaving.
The Timing Question
There is rarely a perfect moment. What helps is having real numbers in front of you instead of a feeling: what your home would likely sell for today, what you would net after costs, and what you would actually be buying. Once those are on paper, the decision gets smaller and easier to make.
"But I Have a Great Interest Rate"
This is the objection I hear most, and it's a real one. I'm not going to wave it away. The better question is what it costs you to live in each house: the payment, property taxes, insurance, maintenance, utilities, and the time and energy a big house takes. Sometimes the old rate wins that comparison. Sometimes it doesn't. Either way, you should decide on the full picture and not the rate alone.
Sequencing the Sale and the Purchase
The part that worries people most is the order of events: sell first and find somewhere to land, or buy first and carry two homes for a while. I'll lay out both paths for your situation, what each one risks, and where a rent-back or a flexible closing date can help. Then you choose.
"Not yet" is a perfectly good answer. I'd rather you decide with real numbers than put it off because the unknowns feel too big.