Is your baby moving out? If you are channeling your existential emptiness into the project of helping to decorate his or her new space, then there are a few guidelines to keep in mind so you're helpful and involved, but not TOO involved.
Shop your own (free) extras
Chances are you have some duplicates hanging around the house that you could unload for a good cause. Silverware, kitchen tools, small appliances, sheet sets — anyone starting from scratch will be happy for these hand-me-downs to get them going. It will help you declutter and help your child have what he needs in his new home. Win win.
Guide him towards a few key pieces
You have a lot of experience setting up home, so by all means share your hard-learned lessons. Maybe you know the importance of investing in a few key workhorse pieces right away (so they can pay off longterm). Maybe you want to give some gentle reminders about how your kid's lifestyle may not warrant white fabric on the sofa. Speak up, but remember, this isn't your place, so gently suggest options instead of taking the lead.
But don't make all the decisions
The fun part about a new place is making the decor choices; even if they're not all the right choice. Making mistakes may cost time and money but will pay it all back with valuable lessons about your taste. Without the chance to try new things and make decor decisions on their own, you kid won't learn to identify her own taste. The first apartment is the first chance to start down the road towards a signature, life-long style. Don't take that away.
Pitch in some cash if you can (but don't buy everything)
After shelling out for first, last and security, chances are your kid's meager savings will be pretty depleted so a little help with necessities like a mattress or a dresser will be very welcome. But try not to take over and go on a buying frenzy thinking you're doing your kid a favor. A slowly evolving decor plan with a combo of IKEA, the curb and DIY is the destiny of every person starting out. It's not only weirdly fun to see what you can get away with, it's a valuable part of growing your scrappy, budgeting skills
Check in periodically
Note, I didn't say drop in. This is not your house so you probably need to call before coming over. It is nice, however, to offer additional help or advice every so often to make sure that the new living situation is going smoothly. Be clear about what you're offering — whether it's cleaning tips or cash — so the grownup boundaries you two have started to establish are clear.