buy or build

[ME]

should i buy this https://www.aliexpress.com/item/1005007363524269.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.10.46cd0kJG0kJGgp&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40196.404796.0&scm_id=1007.40196.404796.0&scm-url=1007.40196.404796.0&pvid=798b1635-7a9e-4bf8-8054-e9ad203a9801&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40196.404796.0,pvid:798b1635-7a9e-4bf8-8054-e9ad203a9801,tpp_buckets:668%232846%238114%231999&pdp_ext_f=%7B%22order%22%3A%22152%22%2C%22eval%22%3A%221%22%2C%22sceneId%22%3A%2230050%22%7D&pdp_npi=4%40dis%21GBP%2186.13%2144.79%21%21%21763.56%21397.07%21%4021038df617398446842972138e8d21%2112000040440014410%21rec%21UK%212308464272%21X&utparam-url=scene%3ApcDetailTopMoreOtherSeller%7Cquery_from%3A
or build this?
https://github.com/AndrewBCN/STM32-GPSDO

[Kean]

First, please clean your links before posting - all that tracking junk after the ".html?" is not needed.

Second, without telling us more about your reasoning and requirements I would have to just say... Yes.
Buy or build, either one, or both.

I would buy the completed one if I just wanted a working solution.  It seems reasonably priced compared to some others, and from the review photos the internals look easy enough to repair/modify.

I would probably only go with that particular github design if there was something special about it that suited my needs.  It doesn't seem to have a ready to go PCB layout, so it will be a bit more work to get assembled, but that could make it more rewarding if you have the available time.

Another one to consider is the one in this thread.  https://www.eevblog.com/forum/projects/budget-gpsdo-a-work-in-progress/
I will note the authors of both published designs by MIS42N & AndrewBCN discuss things in that thread, so it is worth a read.  Most of the magic is going to be in the software.

[Wallace Gasiewicz]

I am not an engineer, just a hobbyist.    I am admittedly ignorant of a lot of things EEs know.     
I built a GPSDO out of junk I accumulated using an old  OCXO and old plans for the old GPS unit. My unit is basic and does not involve software.   
It works BUT:     
I think I would have been better off financially buying a good GPSDO like the Leo Bodnar.  Even though I had most of the parts.   
I think that the PS is a bit critical, I get a much cleaner signal on harmonics on a spectrum analyzer when using an old linear Lab PS than with the brick I used.       
I intentionally wanted lots of harmonics because i needed a 440 MHx (something like that) signal to "calibrate" another instrument. I did this with a SAW filter and an RF amp.     
I believe the quality of the OCXO is important also, perhaps an older unit that has aged would be helpful.     
A good GPS unit with known good reception is very helpful.     
Antennas for these things are quite variable in their performance also.

[Messtechniker]

I usually consider the "Use frequency-to-cost" ratio.

Items I use frequently or which are ceap, I buy. Like DMMs, LCR meter, lab power suppy, signal generator, scope and the infamous transistor tester, battery chargers.

Items I need but use infrequently, I buy second hand or repair. Like Psophometer, wideband AC milivoltmenter.

Otherwise very expensive or not readily available items, I build. Like audio analyser (soundcard + input and output amplifiers), transistor curve tracer, opto isolation amplifier, voltage regulator tester, opamp tester.

[Overspeed]

I usually consider the "Use frequency-to-cost" ratio.

Items I use frequently or which are ceap, I buy. Like DMMs, LCR meter, lab power suppy, signal generator, scope and the infamous transistor tester, battery chargers.

Items I need but use infrequently, I buy second hand or repair. Like Psophometer, wideband AC milivoltmenter.

Otherwise very expensive or not readily available items, I build. Like audio analyser (soundcard + input and output amplifiers), transistor curve tracer, opto isolation amplifier, voltage regulator tester, opamp tester.

Hello
I agree , you can also add , time to do , sometime orders / shipping time / shipping costs pre assembly testing / final assembly can be a important factor regarding time .

On cheap equipment '' ready to use '' except if you want to learn , best is to save time .

Regards
OS

[Doctorandus_P]

That is a question you can only answer yourself.

Buying a gadget has advantages. It "usually works out of the box", and it also has an enclosure, power supply, etc.

DIY has the advantages that you can learn more from how it works, you can modify it (I assume source code is available).