The HoneyWell 50150N is supposed to be permanent and can be vacuum (not wash). Like you I am skeptical.
My plan is;
1. I am using 2 pre-filters. This should help to extend the life of the hepa filter. The airflow is still quite good with 2 pre-filters.
2. The hepa filter is supposed to last 2 to 5 years.
3. I plan to try to vacuum but will need to ensure that the vacuum cleaner do not suck and then blow the fine particle into the air. Best to do this outdoor and with a N mask on. I also will be using a powerful vacuum cleaner with a water filtration system (I have a rainbow cleaner). Alternatively use a VC with a hepa filter.
4. If the above fail, we can always get a new air purifer. A new air purifier (50150 or 17000) is about US$100 and you probably need to pay half of that in getting just the hepa and pre filter. After 5 years, getting a new system may not be a bad idea.
My Sharp KC-840E is still going strong and no funny out of balance motor shaft sounds after 6 years of continuous daily 12-hr operation. Brushless DC motor.
2 prefilters is good. Wrap one more layer, preferably the second layer is finer. I am not sure how coarse/fine the Honeywell prefilter is, but can experiment with the 3M Filtrete or those Duck brand polyurethane foam aircon filter that you can get at 0.96usd from AMZ.
Actually the Sharp air purifiers have 2 prefilters. The first one is those mesh net type the stuff that you find in aircon fan coil units.
Then on the Sharp HEPA filter itself, the side facing the airflow side also has a very thin but very fine fibreglass mesh kinda netting. Something like your surgical mask but much thinner. Just designed to block a wee bit of dust, but that kind of dust that's blocked is way finer than what can be blocked by the regular air-con FCU mesh type of coarse prefilter. It is this layer that needs to be vacuumed (in addition to the outermost prefilter, of coz).....when you touch the dust it is the fine powdery type.
HEPA layer cannot be vacuumed. Also very sceptical that can vacuum, what actually can be vacuumed is that super fine layer of powder dust that accumulates on the "previous" mesh filter I guess. I guess if I make a super rough guess that's like 10 microns? HEPA is 0.3 microns MPPS worst cast scenario, I posted a link before that it can do even 0.01 to 0.1 microns, those are really lodged inside the HEPA filter.....be it HEPA10, 11, 12 or 13.
But I think only the Sharp HEPA filters have this additional very thin layer of prefilter on the HEPA itself (in addition to the net/mesh prefilter on the air purifier covering). Others don't have, like my Novita.
Seriously, also common sense lah...
you see the Honeywell HEPA filters, the mini pleating is some 2 inches deep into the filter, how to vacuum man? The majority of the HEPA doing the work is really those mini-pleats, which aims to increase the surface area and those minimise pressure drop across the filter. Now if our N95s also got mini pleats, that'd help heaps regarding folks kaopeh say difficult to breathe.
The rainbox vacuum shd be good lah.
I think might not be able to push the Honeywell HEPAs to 5 years, even though they do have a lot more volume than say even the SHARP ones. I'll do a calculation soon. Maybe 2-3 years?
The Novita NP501 and I have also see then NP611i, I believe that size of HEPA is just maybe 8 months max (12 inch by 9.75 inch by 0.75 inch), my standard...before I buay tahan either the smell or drop in airflow (noticeably). 12 hrs per day....then add once per year super haze episode of 200-400 PSI.

Really, that dense haze episode really clogs up quite a bit of the HEPA.
My vacuum cleaner is those regular Philips one you see in OG ba..... just that it uses S bag and also the Electrolux/Philips exhaust series "system".
So in the stores got Philips H10 vacuum bags and then H13 exhaust filter. So no issue there.
The exhaust is this one (it's still available, just have to click on the "9 new" link...the Amazon.com add to cart is inside) :
Now is 11.64usd. I got it for 9.18usd.

SG retail is S$45.

Amazon.com - 3M Filtrete Electrolux S / Eureka HF-1 HEPA Vacuum Filter, 1 Pack - Household Vacuum Filters Upright
HEPA-10 S bag. (Electrolux) You can get the Philips H10 bags in OG and Taka Best Denki.
Amazon.com - Genuine Electrolux Anti-Allergy s-bag EL202F - 4 bags - Household Vacuum Bags Upright