I think many of us get trapped in this - I know I used to do it quite a bit and art supplies was also one of my impulse buys but I did use them, probably not as much as I should have, but I still have them all.
As for your bike, well I think you need to weigh it up- are you ever going to use it? If not, if looking at it doesn't inspire you to use it, then sell it. Sell it as it, don't spend extra money on it. The longer you keep it, the less you'll get back for it as older models tend to decrease in value fast.
Perhaps you need to arm yourself with a list of questions the next time you feel the impulse to buy something that you don't necessarily need.
Am I actually going to use this in the next 3 months? (Be honest) if no, then walk away and don't look back.
If yes, then ask yourself is it an investment into something you are currently interested in seriously pursuing? If no, walk away.
If yes, then ask if this is going to add value to your life or enjoyment of life and then weigh up the price point in terms of value for money.
I've managed to cut down my spending a lot by asking if I really need something or if I simply want it. I haven't bought art supplies for years as a result.
I like to use that too (asking if I am actually going to use this in the next three months).
I am still thinking if I am going to use my bike or really sell it already. I just hope Ill have no regrets after.
Thank you so much for your words...