I guess, Here's my point: a lot of the people who I see in healthy relationships have a mutual understanding about what makes the other happy. And then don't feel guilt when they consider buying something that they like.
Married or not, I've had my fair share of relationships, and I'm no expert, but I do know this: I would personaly not chose to be with someone who made me feel guilt, or made me feel implied guilt for buying something I knew I could afford (time/space/money wise) that makes me happy.
Oh, you were being genuine ...

To answer your question, I would start by asking if you understand the assumptions you make.
Perhaps first is the notion of guilt. You're inferring (see what I did there?) the guilt. Approval != Guilt.
Approval != Begging. Approval can be support or approval can be respect. Again, inferring.
You seem to assume that there is a spousal predisposition to disapprove and that getting spousal approval is arduous and shameful. Inferring.
Then there are big assumptions you make about being able to afford the time, space and money. You seem to assume that everybody is in that same boat, that those are binary positions, and that spouses will, by necessity, agree. The more closely your life is tied to others, the less cut-and-dried things become and the more likely that those people will not see things the same way that you do.
Seeking prior approval is about respect and about recognizing that the most important people in our lives may not share your viewpoint. If they did, things would be boring. It's also a really good opportunity to solicit input and invite participation. IMO, the FIRST person I want to talk to about cab design or acquisition is my wife, not a bunch of strange guys on the innertubes that play old games in big wooden boxes.