The cost of looking established
Before buying the image of progress, ask what the purchase will help you do.

The purchase with a second job
Sometimes a purchase has two jobs: the practical thing it does and the impression it creates. A new device can support your work. It can also help you feel like somebody whose work has already succeeded. Distinguishing those jobs is worth a moment.
Let the need explain itself
Write down the problem you expect the purchase to solve. Can you describe that problem without mentioning what other people will think? What would improve in the work itself?
This does not mean every enjoyable purchase needs to earn money. Pleasure can be a valid reason. The point is to recognise your reason rather than disguise an image purchase as a business necessity.
Make room for the less visible investment
Practising, improving a process, following up with a customer, or completing unfinished work may create less excitement than a new object. They may also be closer to the problem you are trying to solve.
Before spending, compare the purchase with one practical action you could take using what you already have. Choose deliberately. This is a reflection on spending motives, not personal financial advice.