Is this Upwork job worth bidding on?
Short answer
Only if four things hold at once: the pay clears your floor, the client has spent real money before, the proposal count is still low, and the required skills are ones you can evidence. Fail any one of them and the expected value of the bid drops below what the Connects and the writing time cost you.
Most bidding advice is about writing a better proposal. That is the wrong end of the problem. The decision that moves your income is which jobs you refuse to bid on at all.
The arithmetic is unforgiving. A proposal costs Connects plus roughly 20 minutes of your time. At a $40 hourly floor that is around $13 of time against a couple of dollars of Connects, so the writing, not the Connects, is the real cost. If your chance of winning is 2%, a $500 job returns an expected $10 against a $15 outlay. You lose money by bidding, however good the proposal is.
That is why the four tests matter more than the cover letter. They are the inputs to the only number that counts: the value of bidding, against what bidding costs you.
Test one, the floor. If the top of the advertised range is under your rate, the job is not underpriced, it is not for you. Negotiating up from a posted budget almost never works, because the client has already anchored.
Test two, proven spend. A client with zero total spend and no verified payment method is the single most expensive profile to bid on. They may never hire anyone.
Test three, competition. Proposal counts are shown in buckets. Under 5 is worth moving on quickly. Over 50, with interviews already underway, means the shortlist is forming without you.
Test four, evidence. If you cannot point to one near-identical piece of work with a number attached, you are competing on price against people who can.
Related questions
How many Upwork proposals should I send a day?
Fewer than you think. Freelancers who consistently win send under 12 a day, all inside a narrow category. The bidders sending 30 to 40 a day see reply rates of roughly 2%, which makes the channel close to unprofitable once Connects and writing time are counted.
Does a longer proposal win more work?
No. Length is not the variable. Evidence is. One specific, comparable result with a number beats three paragraphs of enthusiasm.